movesets are the moves your pokemon know.
there are a few ways to get a moveset.
one way and the easiest way is by level up.
another way is by breeding. for this method breed a male pokemon thats knows the move you want to pass down and breed it with a female pokemon that you want the move to be
passed down to. for more info check out this link http://pokemondb.net/mechanics/breeding
one more way is by move tutor. they usally ask for something like a heart scale or shards or they will teach a move for free but it can only be learned once.