Betting Steps

Call
Betting enough to match what has been bet since the last time you bet. An example would be if you bet 25 cents and somebody than bid 35 cents when to you you would owe 10 cents . If you Call than you would put the amount that you owed into the pot and you would stay in the hand.

Raise
When you raise you first put enough in the pot to match what has already been bet and then you would raise the pot by putting an additional amount in (a friendly game would usually have a limit to how much money you could raise). So lets say the initial bet was 25 cents, you would have to put in 25 cents and than say I'll raise you another 25 cents. Now the other players will either Call, Raise, or fold.

Fold
Dropping out of the current hand and losing the possibility of winning the pot. You don't have to put money in and you would only lose the ante, if its on the first turn, or whatever you put in the pot later. As the Kenny Rodgers song says, "you gotta know when to fold them." Sometimes it is just better to get out then waste good money on bad cards.