You can find the URLs for each of your projects by clicking the My Profile link on the top-right of your Spira instance and then looking at the TaraVault information for your user for the current project. If you don't see the project you're looking for, please have your administrator add you to that project.

In that page it will display the special Subversion URL for accessing TaraVault for the current project along with your TaraVault login/password.