Freeze mage is actually very difficult to play. Unless you are not a multiple legend player I would not really recommend playing it. Same goes to any kind of rogue. Try easier decks first. One of the very important stuff with freeze mage is to mulligan correctly (different vs aggro than vs mid range than vs control), second one is to be able to think at least 2-3turns ahead. (not taking into consideration just your cards but also what opponent can play - Loatheb, heals, smork, etc...)
in this meta full of druids few wars and a lot of face shammans I would not really recommend playing it unless you are already very skilled at it.