Assume your second part is EPA. This is End Point Adjustment, sometimes called travel. This is an important part of car set up. It controls how far the servo(s) moves, independently in each direction. For example on the steering, you want to adjust it so you get full steering both left and right, but don’t overdo it and bind up the steering and servo. Suggest leaving just a little clearance to avoid binding. If you use subtrim to center the servos, set EPA after subtrim adjustments.

EXP is a more advanced adjustment, frequently not used, suggest not getting too concerned about it to start with. It is exponential. It changes the sensitivity of the controls around center compared to full travel. Set one way the controls will move less with small movements on the radio, but then they move quicker at large movements. Other way will make it more sensitive with small movements, less so with large. Difficult to explain well, hope this makes some sense. If interested maybe the best thing is to just experiment with it. It’s a personal thing, I almost never use it, some do routinely. Suggest using in moderation if interested.