How do I get a build reviewed for external testing?

I'm confused, and I can't find instructions.

I have a build for internal testers. That works great!

I created an external group, "Beta".

I click Beta. I can set up testers. But when I go to builds, it says "No Builds Available"

I filled out the test information form.

I don't see any buttons like submit for review.

What am I missing? Thanks in advance!