Click on "Storage browser" in the left navbar, and go inside the bucket
Now, the painful part ... Click on the 'triple dots button' on each file, then click on Edit bucket permissions in the menu.
If you are more of a CLI guy, it's probably better to do it that way :-) More info in
gsutil alc on this page.
Add the 'Teevity ServiceAccount email' as a User with Reader permissions
Teevity ServiceAccount email address