The Templates library is exclusively for slide decks — no other file types can be uploaded here.
You can add slide decks to the Templates library in three ways:
Sync a folder directly to the Templates library.
All slides in that folder will automatically appear and stay in sync.
Sync a specific file directly to the Templates library.
Manually add a slide deck by uploading it directly to the Templates section.
Once uploaded or synced, all templates will be available for use inside the Deck Builder.