Sounds like you've already made two good choices, the set and posting here!
Any question ask and you will get good help no matter how simple it seems, usually the terminology makes it sound far worse than it is. We can post pictures or even wiring diagrams to help you out.
Basically The things to be aware of
are:-
Most makes are compatible but not all.
If you are just starting then Hornby, Bachmann, Vitrains, Dapol locos and stock are good bets.
For track Hornby and Bachmann are ok but the best overall in my opinion is Peco especially for their points as they are much more reliable in the longer term.
Radius with certain bigger locos,
You can check what radius they require in the catalogues. The overhang when your longest piece of stock, (ususally a coach), goes round a corner so that when you get two loops stock on the each track doesn't hit each other. Test this with the track laid out before pinning it down and you can easily adjust the clearances.
Points & power
I'd recommend starting with Insulfrog points as supplied by Hornby, Bachmann or Peco as it simplifies wiring, (Peco also do an electrofrog point but you need to do some extra wiring for passing loops or you can get short circuits)
If you have a crossover between two loops of track powered by different controllers you need to isolate the join between the two points. You can use just insulfrog points but to run from one loop to another one controller must be turned off completely or the two controllers will short out when the circuits are joined by changing the points.