I've been asked to create a "map" for staff members. Help me brainstorm?

My manager tasked me with creating a plan for staff members for when the store is slow. The idea is that, when the store is slow, each staff member will be in charge of an area of the store and work on tasks in that area. They’ll become knowledgeable on products in that area, keep it clean, help customers there, etc. It’s a pretty small store and we usually have two or three staff members at a time. This will help keep everyone organized and on task and ensure that they’re on the sales floor as much as possible.

I’ve never worked on something like this before but I’m excited to be in charge of a project. It’s pretty open-ended; the description in the above paragraph is about all that my manager gave me.

I’m thinking of dividing the store into three sections (for example, coffee bar, grocery, and sandwich station) and about ten tasks they can work on in each section, from most to least important. The store is about as big as a Starbucks, but we have a small gourmet food section and make coffee, sandwiches, and salads.

I’m in charge of re-training the staff right now; the management wants them to be more engaging (approaching customers, offering to help, suggesting products) and more productive. I’m working on training in all areas, like product knowledge, customer service, and sales, but I would appreciate suggestions there as well. I just need help organizing my thoughts for this specific project.