American Audio VLP-300 Power Amplifier question

[cubanorocker316]

Hey guys, I've never used a power amp before and was wondering how it works. If i buy one is all i need a cab ? or would i still need a head, and also if i had a head, would this thing make it louder and clearer ? or one of the 2 ?
thanks in advance for the help!

- Lou

power amp -

http://www.musiciansfriend.com/product/American-Audio-VLP300-Power-Amplifier?sku=803183