First, you get one QS, Ts, and snack per person per night of your hotel reservation- so if you have 7 you have a 7 night/8 day reservation, right? (Some people think it is tied to days, so just clarifying!)
As PP said, booking ahead can help you keep track of it. Plus, in the booking process, it tells you how many credits each place is. Allears is also a good place to reference this, too- as PP said.
Every time you use a credit- TS, QS, or snack- you will get a receipt. You can look and see how many of each are left at the bottom of the recepit and track it that way.
Keep in mind that, other than TS, you don’t have to all use your credits at one time. You could buy 2 QS meals for 4 people to split, for example- and use 2 snack credits to get drinks for the other 2 people.
Each QS and TS meal comes with a dessert. They have changed the rules so that you can substitute a soup or salad at the TS and anything on the menu that is a snack credit at a QS.
Hopefully this is helpful and not overwhelming?