To connect new apps click on Settings > Apps & Projects in the navigation menu, then go to the Connected Apps tab.

From there you can see the list of available apps. Click Connect to add new apps.

Clicking Connect will redirect you to an authorization page on the application provider side. Click Authorize to allow Keypup to enable the connection (example with GitHub below).

After authorizing the connection, you will be redirected to the projects page on the Keypup side. From there you will be able to connect projects to Keypup.