I thought I need just this link https://play.google.com/store/apps/details?id=com.here.myapp.name
to download an app from Play Store, but when I click on it fro
The link of testing will be https://play.google.com/apps/testing/packagename and you can find that in Alpha/Beta publish tab.
https://play.google.com/apps/publish --> Select app --> Release Management --> App Release --> Alpha/Beta --> Manage --> Opt-in URL (URL for testing)
Updated to add tester (Close test)
Add testers
Here's how I found it (with help from Scar Coder's answer)
Expand the 'Manage testers area'
Copy the Opt-in URL:
On the Play Console, there is an opt-in url that needs to be sent to the internal testers before they can be able to download the app
App should come to the published status before the Opt-in URL is enabled. You can get your app status in the small '?' symbol or in the drop down box location above the page. Google takes some time to review the app before publish after you submitted it.
The initial release time of up to 48hrs is what confused me, and is not well communicated on the Play Console:
Searched for "android Available to internal testers", as Play Console stated exactly this, without the link providing an app (see original question).