Hi 101,
In this stage of training it's really easy to get hung up on these details - I remember it well!
I would say this issue is generally not a problem. It just depends where you're landing.
If you're at a full ATC place, you will be told what to do before you've had a chance to worry normally - and if it's a big place, be prepared to be told to take second left, first right to taxiway charlie, cross the inactive, 3 rights, 3 lefts, back across the other way to avoid the taxiing heli, advance to Mayfair and park behind an aircraft you've even never heard of let alone be able to recognise...
FISOs also have control of the ground and should let you know what to do if you don't know the place, but if they don't, just ask. It's not generally as complicated at these big places, though!
If it's A/G, I just do what's sensible but I normally make sure I'm not causing problems by doing so by talking to them.
If unsure, I get off the runway when I'm definitely ready to and then sort myself out. You're supposed to vacate as soon as possible and this is common sense anyway. However...
One thing it's very important not to do is to worry so much about where to turn off that you don't pay attention during the landing run, which is part of landing, the most difficult manoeuvre in normal flight, and when you're still carrying a lot of energy as speed.
If it freaks you out, have a look at the plate before you go and plan in advance I'd say.
