How can I make an project collaborative?

If you need to convert an old project into a collaborative project you can do it by accessing the project from the MANAGE tab. 

Once there, click on the sharing options and choose the Collaborative Editing option. 

Note: Only the administrator or subadmin of a group can access to change the project type.

Differences between Contributor Editing and Collaborative Editing: 

Contributor Editing: 

Users with "Contributor" editing rights to a project can view all entries within that project, but only retain the ability to edit their own entries. This level of access ensures that team members can reference a project’s contents, but prevents entries from being edited by those other than the entry’s creator. This was the default editing right previously present in Labfolder.

Collaborative Editing:

Those with "Collaborative" editing rights to a project can view all entries in the project and edit any entry in the project. This new editing right, allows lab members to work on entries together and accelerate idea-sharing.