How to add a publisher ?

Hello , I would like to know : 1) How to make it possible for my project to be edited by people whom I designate by the cloud or else because I put my project on cloud but I do not know, if one of my editors wants to access the project, it Has only to import the project by cloud on his pc and there will be a syncronisation or it is only for him that it will apply modifications?

2) If I add a person as a user on my project, he can modify it or you need a manager?

Thank you in advance, (if you do not understand, carefully re-read the questions one by one)