This question has baffled me. PLEASE HELP!

In an ideal Stirling engine, n moles of an ideal gas are isothermally compressed, pressurized at constant volume, allowed to expand isothermally, and then cooled at constant volume, as shown in (Figure 1). The expansion takes place at temperature TH and the compression at temperature TC. The quantity pc/pd=pb/pa is called the compression ratio of the engine, or the CR.
Determine the work done in terms of the CR during the expansion phase.
Express your answer in terms of the variables n , TH , CR , and gas constant R .
Determine the work done in terms of the CR during the compression phase.
Express your answer in terms of the variables n , TC , CR , and gas constant R .
An ideal Stirling engine uses 1 mole of helium as its working substance and has a CR of 10, temperature reservoirs at 100 ∘C and 20 ∘C , and a frequency of operation of 100 Hz . What is its power output?