Hello Flyer54
There is no GA travel card 15 days pass.
I assume you have purchased the Swiss Travel Pass for 15 days.
https://www.sbb.ch/en/tickets-offers/tickets/guests-abroad/swiss-travel-pass.html
If you haven’t purchased the Swiss Travel Pass as a registered user, you cannot view it in the SBB Mobile app. Simply show the PDF document together with your physical passport.
The Swiss Travel Pass for 2nd class allows you to purchase class upgrades for 1st class for half of the regular cost (= half fare). How to activate the half fare for each passenger in the SBB Mobile app? I described it here:
https://community.sbb.ch/d/26418-how-can-i-save-the-info-of-swiss-half-fare-card/2
What do you mean by making reservations? The Swiss Travel Pass is your ticket, it allows free travel at will on all means of public transportation with exceptions of mountain excursions. If you mean seat reservations, then please read our guide to get an idea on seat reservations on Swiss trains:
https://community.sbb.ch/blog/23887-demystifying-seat-reservations-on-swiss-trains-a-comprehensive-guide
Please let us know if you have got more questions.
Kind regards,
Roland