At least this is how I know to do it - you might know otherwise.

The RC stands in the middle of the empty store and yells "Go!" Bribes in the form of candy are given freely. Small toys are also appreciated. By the end of three weeks, you will have the 7 trainers madly rushing about pulling off little yellow paper tags, the staff trying to remember how to run a cash register that they learned about a week ago and haven't touched since, and an RC who's trying to deal with a month's worth of back expense reports that someone else forgot to file. Oh yeah, and some stuff is on the shelves. You win.