Hello Quengonnea51
I suggest to buy a Saver Day Pass for this day, choose the “Full Price without the Half Fare Card”:
https://www.sbb.ch/en/tickets-offers/tickets/day-passes/saver-day-pass.html
Please note that Saver Day Passes are not exchangeable and not refundable.
You must also buy a ticket from Como to Chiasso, take a regional train (normally RE80 and you change in Lugano). You can buy this ticket in the SBB Mobile app before departure.
The Saver Day Pass is not valid for the Pilatus, it is valid only with the bus from/to Kriens or the train from/to Alpnachstad. A reservation is only recommended between Alpnachstad and the Pilatus. You can find more details here:
https://www.pilatus.ch/