Hello marcelltoth
Yes, you can. It is valid on the BOB / Jungfrau railway trains to Grindelwald and Wengen. Also Rigi is included.
You can find its map of validity here. As a principle saying, it covers all solid or dashed red / blue / yellow lines (no grey lines, no dotted lines - on this route no free travel, no discount). It also fully covers public transit in the cities.
https://sbb-tickets.cc/en/tickets-offers/travelcards/ga-travelcard/ga-travelcard-area-validity.html
The Friends Day Pass for Youth is an outstanding offer. Just bear in mind that everyone needs their physical passport or ID card upon ticket check (copies or photos on mobile phones are not accepted).
Kind regards,
Roland