Almost everyone has a Wifi network at home these days. These are usually from the default router provided with the internet connection. The issue with that is the limited range and coverage that these units are capable of. There is where getting your own home network comes in. With a proper home network you will be able to have faster access to any other local devices and have proper coverage throughout your home. There are several methods of setting one up:
You can setup your own local area network. This will require quite a bit of work if your house is not already wired with ethernet cables. For those that do have cabling, you can set up several wireless access points on the same network. Any devices like local storage etc can also be on the same network.
Another method for covering the house would be a whole house wifi network. Wireless extenders are setup at points close to where coverage is not available or bad. These extenders take the existing wireless network and increase coverage. This does come at the cost of speed but given that most wireless network traffic is underutilized, means this is not a concern for everyone.
There is an option to go hybrid. This method also uses extenders but they are setup as bridges. The wireless extender connects to the wireless network and then provides wired access to other devices. This way if there are devices concentrated in a particular area, you can provide them with lan cables from the bridge devices. This is more complicated to setup but also does not requre any wiring.