How do I direct my multisite users to the website rather than the backend dashboard.

How do I direct my multisite users to the frontend of the site rather than the backend and leave the admin bar up so they can use the backend when they want to.

Please help me understand the following:

1. How multisite users can log into the frontend of the main site without being directed to the backend first.
2. How can I leave the admin bar up so it can be accessed by the multisite user from the frontend.

The outcome:
1. Users will log into the frontend and uplaod media and products.
2. The users will have access to the admin bar so they can access the backend if they want.

Thanks,
Nicholas