Microsoft project management software used to plan, manage, and communicate a project schedule and other information among workgroup members, project managers, and other stakeholders.
Dear James,
Welcome to the forum here.
Please first check whether you are using Project Permission Mode or SharePoint Mode.
If you are using Project Permission Mode, you may first add users to the User group and give them permissions to access the specific project.
Thanks for your effort and time!
Sincerely,
Cliff | Microsoft Community Moderator