Odds and Outs
Outs are the card that complete a draw, which means possibilities that you could get the best card in the next round.
So basically I need to calculate how many outs are there that can help me make the draw.
Odds and Pot Odds
Odds means the ratio of the cards are helpless / cards are helpful (i.e. if the ratio is 5:1 which means you could get the helpful cards once for every 6 times.)
Pot Odds is the ratio: the money you could win from the game / the money you pay into the game.(According to the example, the pot has 12$, the bet is 2$, if you want to play the game you have to bet 2$, so the cost is 2$, and if you win, you will get 12 $, so the ratio is 12:2=6:1)
So according to the odds and pot odds you might decide if the game is profitable.
Pot odds > Odds, you can call, otherwise, you fold.
Here is the chart shows you the situation of outs and odds when in different procedure of the game.