When you publish an app for the first time to the server, it may be hard to locate the Web Test link but don't worry, this guide is here to help you.

To find the Web Test Link for your app head to your Google Play Console and to your app's dashboard by clicking on View app.

Once here, go to the closed tests tab (Test and release > Testing > Closed Testing). Click on Manage track for the active closed testing track.

Open the Testers tab and scroll to the end of the page, locate the Join the web section and press on the Copy link button. The web test link is now copied in your pasteboard and you can paste it in the new app form.