Lost signal to receiver?

My boss therm thermostat BRTRF has no buttons at the rear???
Alan, October 2022


done
Manual here:

https://assets.new.siemens.com/siemens/assets/api/uuid:f747d2bf3ade1166c6a122de21cc1de551f0d0c3/bps242rf-faq.pdf

Note where it says Mounting plate must be removed to get access to the back!

Ririyo, October 2022