Favorites can be done by clicking on the 3 dots on the top right corner of the board or dashboard > Add to Favorites."
Or right-click any board in the boards list on the LHS > Add to favorites.
SUGGESTED ENHANCEMENTS
I’d love to have the option (via a checkbox) to keep Favorites open at all times so I can always see them and access them via a single click at any time. I could, for example, jump to high level boards in a single click.
In cases where Favorites in not set to be always open, I’d like clicking on Favorites to toggle back to the last board view I had open - rather than going back to a collapsed board view which requires an extra click to get back to where I was.
i.e. avoid this when I click on Favorites to get out of Favorites