You can have multiple projects in your Delve account, whether created by you or shared with you.
To switch to a different project, or just see what projects you have access to, click the arrow icon in the upper left corner.
A window will open with a list of all projects you have access to. Click on the Project to open it in Delve.
Note: If you do not see a project, contact the project owner and ask them to double check they properly shared the project with you and that you have been given the needed access.