Permissions question

Hi all,

I am a fairly new user to this and would like to clarify something before I carry on down potentially the wrong path.

From what I can gather, it seems that you can give permissions for someone to edit timelines within a layout, but they can only edit timelines they have created(I have an admin account, and a user account, but the user account doesn’t seem to be able to edit the timeline added by the admin), is this correct?

Also, is there a way of granting someone access to edit a timelines, but not have access to resize it?

And lastly, is there a way of allowing a user to be able to edit a timeline in a layout, but not have access to add new layouts?

Thanks in advance