For the set $SL(2,\mathbb F)$, where $\mathbb F$ are entries from either $$\mathbb{Q},\mathbb{R},\mathbb{C} \text{ or } \mathbb{Z}\_p \text{ (p is prime)}$$

How should I start by checking this matrix group is an Abelian group?

First off, what is modulo $p$ prime? (modulo integer n is the set of integers in the set smaller than n and relative prime to n so does modulo p prime implies the set of integers which are prime, smaller than n and relative prime to n? Doesn't make much sense to me)