How can I add multiples users to a collection?

How can I add multiples users (recorded on user collection) to a Event (another collection). Do I need to create as many properties users as the number of users I need to be in the collection Event)?

Depending on how your app works, You could try setting a relationship between the users and the event collections.

I mean, I want to add non logged in users to a collection and then visualise them in a simple list. But the only thing I m able to do is add logged in users.