The prerequisite is that you already have a Polar Flow account. If you have not yet set up a Ploar Flow account, you must do this according to the instructions for your Polar watch.
You can create a link with Polar by clicking on "Integrations" in your profile in the uVida app.
There you must select Polar and then link to your existing Polar account.
If you are not redirected to the Polar page, please proceed as follows:
Click on "App Settings" in your uVida profile and then select the "Clear in app web view caches" button.
The redirection to your Polar account should then work. Then proceed as described above.