Note, make sure you have Voice In extension downloaded already. If you don't have it downloaded, download it from the Chrome Web Store or the Edge Store.
Step 1: Open the Voice In Plus activation page in the Edge browser.
If this is the first time you are visiting this page on Edge, you will redirected to login. Login in to your account that you used to upgrade to Voice In Plus (most likely your Google account. Click on Continue with Google and login using your Google Account)