Sorting by Groups

Hello there,

I hope I can get some help with this task:

I am measuring a Set of Temperature values for different groups of samples.

So the Data I am recording is in Column A, B and C.

FIRST: I want to rank/sort the Temperature values in a descending order for each Group and Number (Column D & E).

SECOND: I want to calculate the average (Column F & G). 

Because I am really new to Power BI, I am happy for every help and thanks for the explanation also.

Best Regards