So tracks laid now its time to learn how to wire a model railway
This can be an easy job, but the more complex the layout the more complex the wiring! For track feeds starter sets will generally come with a track panel already wired up for you to plug straight into the controller, for the more advanced, you will need to solder wires to the rails direct.
If this is your first layout dont attempt to do an ambitious layuout like Kings Cross, start simple, if needs be make a small piece to practice on and test before you start on your layout proper. once you have done one section of your layout test it with a small locomotive to see that it works, before moving onto the next section, this will help with fault finding later.
Its important to get the layout working properly before you move onto adding ballast or other scenery items around the track.
For point motors and other accessories check with the manufactures instructions this also applies to points or turn outs, Peco, the market leader for track always include instructions on how to wire their points and other accessories