@mdubakov reinstalled our instance, and when I logged in, I see we had wiki and tasks by default.
I added project app, and as the little animated gif shows, I created a relation, tasks m:1 projects. I can see the link in the schema/domain diagram.
However, when I make a new board under a project, I cannot select tasks from configure board, cards. At first I did not have a task so I thought this was a problem but, adding a task to the project did not change this.