betting for value = you think you have the best hand and want opp to put more money in the pot.
as opposed to:
betting for info = you think you MAY have the best hand, but looking to opp's reaction to your bet to get more info
bluffing - you don't think you have the best hand, but hoping opp will fold to your bet
semi bluffing - you probably don't have the best hand right now, hoping opp will fold, but if he calls you may end up making the best hand.

Most basic value bet - board is QJT all hearts, you hold AK hearts - you have the nuts, any bet you make is a value bet. On same board, a bet for info might be if you held QJ. You might semi bluff with just the Kh. If you bet with 7s8s, it's a bluff.