You can accept the pending invitations that have been sent to you from the web version or using your Android.
Web Version
On the home page, click on the Envelope icon ✉ at the top right of your screen to access the list of your project invitations.
Android Version
Click on the three bars in the top left of your screen
Click on "Invitations"
Accept to join the project
☝ If you still can't find the invitation to the proper project, something may have gone wrong, ask the project creator or an administrator in the project to resend the invitation to you.
👉 If you successfully accepted the invitation, start to work with Bulldozair :