Step 1: Make sure your business has a Google Plus Business page.
Check if you have one here
If you do, click on it to make sure it is verified.
If you do not have a page, set one up here
Get more information about starting a google+ page for your business here

Step 2: Book your virtual tour here
Shoot takes approximately 1 hour.
Try and schedule for a time when your business has the least amount of people in it.

Step 3: Prepare your business.
Get it just the way you like it. Have your merchandise visible and organized.
Make sure your employee's are aware that the walkthrough is going to happen and explain to them how it works.
Have select merchandise picked out for the still shots.