1. You login
   
2. Click Explore Projects
3. Open your project 
4. Click Invite People
5. Type the email address of the person you want to invite and click Invite
6. The other person (Person B) will receive an email invitation 
7. Person B should click the link in the invitation to accept the invitation
8. Person B will need to login
9. Person B will be added to the project

Someone requests to join your project:

1. Person B logs in
2. Click Explore Projects
3. Open the project you want to join
4. Click Request To Join
5. Input a reason and click Send Request
   
6. You (Leon) will receive an email notifying you of the request
   
7. Click on the link in the email to go to your requests page
8. Click the link in the Actions column to Accept Request
   

In either scenario, you can tell if someone has been added to your project by clicking on the Members link below your project's icon.  All members will be listed in the dialog that opens.