To manually tune Jazz FM on your Freesat box, you must go to the ‘add channel’ section and input the below numbers.

The numbers needed are:

Frequency: 11686
Symbol rate: 22000
LNB Polarisation: Vertical

FEC: 5/6

If those details go in to a manual tune (every box is different on how to get to the "manual tune" menu) then Jazz FM will appear as one of the additional services.