Multiple Windows users one account.

[nybbster]

I need help to understand how i should set it up. And i want one account to be the admin and decide what games the other users can play. All of the users is on the same machine. And if possible I dont want the other user to use steam and purchase and change the settings of the steam account. Please help.

[miamew3]

Sounds like your looking for Steam Families, here you can set up group with accounts to share games.
You can add users as child accounts and control what games they can play, what they have access to on steam etc.. If they want to purchase a game they have to send a request to the adult in the group who can grant or deny the request.

You can read more about it here
https://help.steampowered.com/en/faqs/view/054C-3167-DD7F-49D4