Hi, Richard!
We LOVE the
Disney Dining Plan! (Yes, I shouted "love"; we are very strong fans...)
In short, Guests on the Disney Dining Plan receive one Table Service entitlement, one Quick Serve entitlement and one snack entitlement per night of stay. Each Guest on the reservation must be on the Dining Plan as well. As such, if you stay the nights of August 26-August 31st (checking out on the morning of September 1st), each Guest in your party will be entitled to 6 of each of the above-mentioned items. Those totals are pooled into one total for the reservation, so if you have 4 Guests in total, your "pool" of entitlements will be 24 Table Service meal entitlements, 24 Quick Serve meal entitlements and 24 snacks. All of these entitlements are activated the moment that you check in (keep in mind that you can check in at your resort at any time on that first day; you don't have to wait until the afternoon to do so.) Those entitlements will be placed onto your Key to the World Cards, which also act as your room key and, perhaps, your park tickets. On midnight of the day you check out, Sept. 1st in your case, all unused entitlements expire.
How you use those entitlements is entirely up to you. We've done a Character Breakfast (Table Service) in the morning on one day, then enjoyed an early Table Service dinner that same day, using 2 TS entitlements that day. We simply make up for that by enjoying 2 Quick Service meals some other day. Because the all of entitlements are activated from the moment of check-in until midnight the day you check out, you really are free to use such entitlements any way you'd like.
If you need suggestions on how to make those Quick Service entitlements feel more like Table Service, just send me another question; I'd love to help you maximize your meal options as you enjoy the Disney Dining Plan!