In the Collaborate Tab, select the name of the collaborator you wish to grant download rights to.
You'll see Collaborator: (their name) at the top of your screen. Underneath their name you can check the box to allow them to download the full timeline and/or the tailored timeline (venues/vendors). This is called "wedding party timeline" for clients.
The full timeline will allow them to download the entire timeline, while the tailored timeline will only download those items they have been assigned to.
You can uncheck either box at any time.