FWIW, I think this info is right, but I'm not 100% sure, so it's always good to get a second opinion.

Pot odds is how much you are paying in relation to how much you given a chance at winning. Therfore if a pot is $40 and your opponent bets $20. The pot is now $60 and you must call $20. So your getting 60:20 odds or 3;1.

Hand odds is how often you expect to make your hand. You count your outs first (such as flush draw = 9) then you apply a method that determines how often you hit. There are a few different methods. The 2 and 4 rule. (ask if you dont know and we will explain). So you figure out that with 9 outs to come and one card to come you will hit ~18% of the time (4:1). So since your pot odds are less than the chances you make your hand you aren't etting proper immediate pot odds to call.

HOWEVER, there is such a thing as implied odds. So since on the turn you need 4:1 odds to call, but are only being offerd 3;1 youa ren't getting immediate pot odds. However, if you expect to make enough on the river the times you do hit then you can profitably call. In this instance you would need to on average make an additional $20 on the river to be breakeven. Well since the pot will be $80 on the river if youc all the turn, then it's reasonable to assume you will make more than that on the river the times you hit, so it's probably a profitable turn call in most instances.