Will this tool come with instructions?

I have bought some nice Fossil watches. They all need batteries. I would have to travel a good distance to go to a Fossil store. I would like to order a tool to open the back of the watch to find out what size batteries to order. I am not a jeweler so have no idea how to open the back. I would like to order the tool to open the back of the watches, but want to make sure there are instructions on how to use the tool. Any help you can offer would be greatly appreciated. Thank you!

поNancy George