I did the Beluga & Walrus encounter in 2018 when it was a combined encounter. For the beluga portion, we headed backstage to the indoor part of the beluga exhibit. Each person took a turn kneeling at the edge of the pool with a trainer, asked the beluga to do a behavior or two, then tossed him a fish. When it wasn't your turn, another trainer answered questions while you watched other participants.
We also met an adult walrus in the backstage area and fed him a fish, and got to see the baby walrus in an indoor space. I don't know if they do longer or more with the belugas, now that those are separate tours. I thought our encounter was well done and worthwhile.