When I ad my force pack cards to my deck do i need a certain number of cards in my deck or does it vary?

Also, Does each side have a different total of cards becasue my decks do actuallly?

10 sets minimum as per rule book page 28.

In addition to what Toqtamish stated, there is no max to the amount of Objective Sets you can have. So if you really wanted to, you could take every Sith Objective Set there is an make a massive deck. However, 10 Objective Sets seems to be pretty balanced and you have a decent chance to pull the cards you will really want in a game.