Steps
Select the Move between projects button on the Contact’s profile page
In the popup it will list the projects that exist within the organisation
Select Enrolled in the dropdown list next to each project add the contact to that project
Press Close
Considerations
If other states are enabled on that project (e.g. Waiting List, Alumni, Declined), you will also have those options available
If a contact is already within a project, the Remove from project option appears. Clicking this will remove the contact from the project. If the Declined state is enabled on a project, consider whether you wish to remove the contact from the project or move them to the Declined state of that project