Could you give me a simplify example on how you calculate the values of recall and precision?

[tenlives]

Hello,
Suppose that I have got the profiling file which contains the abundance value at each rank with taxa. For example, at the rank 'Phylum', there are many taxa profiled. If I calculate the recall value , is it a corrected way to calculate the each taxa recall value and then calculate the average value? or just calculate the recall rate on the rank 'Phylum' as a unit?
Thank you !