Once you have users created, you can use the Security tab of the canvasser view to specify what portions of your campaign they can access. Keep in mind these settings only apply to website access. If you want to adjust which script they see on a device, use the script drop down under Account Settings.
After clicking the Security tab, you'll be presented with their security settings. Here you'll be able to narrow down as specifically as you like to set their level of access. This follows our hierarchy for campaigns: Customer, Campaign, Location, Script.
By moving one or more of each to the right side, under assigned, you'll set what this user sees when they log into the website. If you want to give them access to an entire level, such as a whole campaign or location, move all the items to the left. The checkbox that says "Restrict xxx Access" will uncheck, and they'll automatically have access to everything below that in the hierarchy.