ElinaH:
Maybe after installing the add-on, you need to go into the
Work Environment and add the commands. Go to Work Environment > Command Layout Schemes > Menus: set List to All Commands by Theme, then scroll down to 17 Add-Ons > Google Earth In-Out > Google Earth Connections.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
David