In order to make use of the Autodesk Platform Services (APS) integration, you first have to log in. This can be done with the middle toolbar button.
Once logged in, you'll be able to see your name in the main export panel.
To store an export in your current project, make sure the "Export Location" option is set to "Upload".
To log into your Autodesk account, open the left menu and click on "APS Login".
Upon successful login, you should see a notification in the bottom-right, as well as a greeting and your profile picture replacing the "APS Login" button.
Once logged in, when you open the "Spawn Asset" panel, the remote assets section will begin to search your projects and show any and all Synthesis assemblies available for importing.
After you've imported them for the first time, they will be saved for later use and won't require APS login to access so long as they stay saved in your browser.
If you need help with anything regarding Synthesis or it's related features please reach out through our discord sever. It's the best way to get in contact with the community and our current developers.