When you install a hub on your local network it is just a matter of plugging the hub into the power and connecting network cables between the computers and the hub. The hub will automatically rebroadcast all the signals that it receives to all of the computers that are attached to it so that the one for which each message is intended will receive and act on it while all the other computers will also receive it and ignore it.
A switch is a little more complicated because it learns which messages are intended for which computer and will then direct the messages only toward the one for which it is intended rather than broadcasting it to all of them. Most switches these days come combined with other network devices.
In this particular instance we are going to look at how you configure things when your switch is combined into the one unit with a router and wireless access point.
The particular wireless router that I installed is a Netcomm NB504 but I am not writing specific instructions on how to set everything up (you can get that level of info from the manual that comes with the device). Instead I am going to cover at a higher level those parts of what can be configured that you need to look at so that you will know what parts of that manual that you need to worry about when you first set it up.
The first thing you need to consider is the IP address allocated to the device on your network. The device will have a default address preconfigured into it. If you are setting up your network using an address range that includes that address and that address isn't already used then you may as well use that address (all of the devices I have seen use 192.168.1.1). If you want to use a different address range for your network or if that address is already in use then the first thing you will need to do is to change the IP address of the device.
In my case I am using a different class C network and so my existing network couldn't even see the device. To rectify this it is necessary to log into one of the computers on your network with Administrator access and change the IP address of that computer so that it is on the same class C network as the router. Let's say I am using the 192.168.5.0 class C network for my LAN and the computer I decide to use to do this has the address 220.127.116.11, so I change that computer's address to 192.168.1.3 and that puts it on the same network as the new router. I then plug that computer into the new router instead of the existing network and follow the instructions on how to access the router's control panel. In this case it is a web based one and so I access it by typing http://192.168.1.1 into the address bar of my browser. From here I then follow the instructions in the supplied manual to change the IP address of the device to what I want to use (eg. 192.168.5.2). Exiting from the browser now means that the computer can no longer access the device because they are no longer on the same network. I can now change the IP address of the computer back to what it was before and reconnect it to the network. The network can now be reorganised to incorporate the router because the router now has an appropriate address on the network. All subsequent access to the router control panel can now be done using the new IP address that you gave the router rather than the original default one.
I already had another router on my network, specifically a Netcomm NB5plus4 which combines a modem and router into the one unit and so to connect the two together I looped the fourth LAN connection on the NB5plus4 to the first LAN connection on the NB504 This completely bypasses the router function in the NB504 and adds it as a switch onto my existing router and does not use the actual router functionality of the unit at all.
If you are going from a single computer connected to the internet to connecting a network of computers to the internet then you would unplug the broadband modem from the computer and plug it into the WAN socket on the router instead. You then need to go into the WAN settings on the router control panel to set up the same configuration settings for the router as you had configured on the original computer. With the original computer and any additional computers connected via cable to the LAN connections on the router all of those computers will now have internet access the same as the original computer had before. Note that you will need to have at least one computer hard wired to the router to be able to do the setup at least until after you get the wireless setup completed. This takes care of the actual basic router configuration.
If you are using the router as a router with a modem connected to the WAN port then you may also want to look at some of the other options that the unit provides such as firewall settings.
The final step in the process is the configuration of the wireless access point. If all of your computers are hard wired to the LAN ports then you might as well turn the wireless part off since you have presumably only obtained a wireless router in order to have wireless capability in the future (or because you couldn't get a router without it). If you are going to use it then it should work as supplied but will be extremely insecure and will allow anyone with a wireless network connection who comes within range to connect to your network. You should therefore change some of the settings so as to make your wireless setup more secure.
The first thing you need to change is the SSID. This is the field that provides a name for your wireless network. If your access point supports it you will also want to turn off the broadcast of the SSID so that people will need to know what value you gave it in order to connect to your network.
The second thing to change is to turn on security using the highest level security option that all of the wireless devices on your network support. In my case I selected WPA and set up a passphrase containing upper and lower case characters and numbers. People will also need to know all of that information in order to connect to your network. That makes it much more difficult for people to connect without your permission since they are unlikely to know what values you have it set to and therefore can't duplicate them to connect the way they could if you left it set to the defaults.
The last thing to consider to make it more difficult to connect is to use static IP addresses for all the devices on your network rather than having them allocated dynamically. My router was configured by default to automatically allocate addresses to connecting devices as they connect. By turning that option off and making sure that each device on my network has a different static IP address defined for it a person trying to connect to the wireless network would also need to manually allocate a static IP address that isn't already in use on my network in order to be able to connect (assuming they found a way past the other security). My router also has an option for allowing and disallowing access for specific IP addresses on the network so by configuring that to only accept the IP addresses that I manually allocate to each wireless device that I am using I can reduce the chances of someone else being able to connect even further.
Now all that remains is to configure your wireless networking on the various devices you want to be able to connect. You will need to know all the information that you just used in setting up the access point in order to apply that same information in setting up a profile on your wireless device so that it can connect.