Can you help me understand?

So, after i finish fourth semester, then take comp(hopefully i pass), how long should i take to study for step 1, i was thinking 2 months. Is that too long? Also after i take step how long will it be before i start IMF, then how long after i finish IMF do i start rotations.
i was thinking rotations started on the same schedule as semesters, so one starts in fall, the other in spring, kind of thing.

Thanks