Correct way to use actions with ember-bootstrap

Created a new ember octane app (3.15) and using ember-bootstrap with it. I am using a modal like so

<BsModalSimple
  @open=true
  @title="Create new podcast"
  @closeTitle="Cancel"
  @submitTitle="Create"
  @size="lg"
  @closeButton=false
  @fade=false
  @backdrop=true
  @backdropClose=false
  @renderInPlace=false
  @onHidden=
  @position="center">
</BsModalSimple>

This works but I get an error which says

Do not use action as . Instead, use the on modifier and fn helper.

What's the right way to use an action in this scenario? I've tried this but it didn't work