His default controls aren't consistent with what you expect with a tank, they sort of tried to make his shield a right click like Rein's but that works against him to make him feel a lot more confusing then he is.
If you switch his controls to act more like Zarya or Orisa his a LOT easier to play and tends to fit with how you expect him to work when you pick him up.
I made a simple guide on how to do that here: https://imgur.com/a/3CT5pfs
(Would have linked it directly but subreddit rules don't allow that)

