From the navigation menu, click on 'Admin Console'
Click on the 'Staff' Tab
Click on a staff member's name to open their profile
Go to the Access Tab
Choose any product you want to configure access to and click on the 'Pencil' icon on the far right of the screen
Make any changes you need, then click on 'Apply'.
Once you have configured the permission levels, scroll to the top and click on 'Save'.