To add a talk to Favourite talks, clickin its top right corner:
The star icon will change to, which mean the talk was marked as a favourite. You can click the star again to remove the talk from Favourite talks:
To view all your favourite talks, click your profile picture at top-right of the screen and choose Favourite talks.
The Favourite talks page contains all talks that are marked as favourite across all your Confluence spaces. Clicking Talk icons activates corresponding Talk comments on the sidebar. To view a talk on a Confluence page, click the link with the name of the space and the page, where that talk is locatednext to the Talk icon. Besides browsing, you can edit, reply to, resolve, archive, restore and manage viewing permissions right on the Favourite talks page.