Where do alpha testers download Google Play Android apps?

Question

I have developed my app and have published it through Google Play for alpha testing. As one of the testers I get an opt-in link, where I signed in as a tester. After that I

Answer 1

It should be noted that releasing an alpha app for the first time may take up to a few hours before an opt-in link is available and invitations are sent out to the email addresses in your testers list.

From Google support:

After publishing an alpha/beta app for the first time, it may take a few hours for your test link to be available to testers. If you publish additional changes, they may take several hours to be available for testers. [source]

You may want to wait until you have an initial opt-in link before publishing more changes to the app because doing so is likely to increase your wait time for receiving your tester link; or, may lead to your testers testing with the incorrect version.

Hope that clears things up for anyone confused about why they don't have an opt-in link as depicted in screenshots in this SO thread!