Hello Joruzoch81
You have to activate your pass for each day either day-by-day or all days in one step through this website:
https://www.activateyourpass.com/
Then, you can download the generated ticket and save it as a screenshot. Or, you can add it to the Apple wallet.
You can deactivate an already activated day again if you do so until 23:59 the day before.
Kindly note, the Swiss Travel Pass is only valid if you carry your physical valid passport or official state ID card with you. Copies or photos are considered valid and are therefore not accepted.
Kind regards,
Roland