Hi Papiya, and welcome to MySwissAlps!
>> Please can you advise which Mountain excursions are included free or at 50% if I buy a Swiss Travel Pass.
You can download a map from the link below, showing what is covered by the Swiss Travel Pass.
As explained in the legend on the map, red lines are trains, yellow lines are buses, black lines are cable cars, white lines are boats. Solid lines are free, dotted lines are discounted. Discounts are mostly 50%, but only 25% for transport where you see the number "1" inside circle near the dotted line. There are a few grey lines on the map as well, which indicate transport that is not covered by the Swiss Travel Pass. Dashed red lines on the map are railway tunnels, and are on routes that are free with the Swiss Travel Pass.
>> how much do I need to pay for going to the top of Jungfrau
With a Swiss Travel Pass, travel is free as far as Grindelwald or Wengen. The you get a 25% discount on the full fare between Grindelwald or Wengen and the Jungfraujoch. The full-fare pricelist can be found here:
www.jungfrau.ch/filead min/Prospekte_und_Bros chueren/Jungfraubahnen _Fahrpreise_Preisliste .pdf
>> Titlis if I buy the Swiss Travel Pass
Travel is free with the Swiss Travel Pass as far as Engelberg, then you get 50% discount on the gondola to Titlis.
Fares can be found on the Titlis website:
Please note that there is no discount for the Ice Flyer chairlift, which is an optional activity on the Titlis.
You can plan your trips using the Swiss Timetable: