How to use "cuTensorMapEncodeIm2col"

I am try to use “cp.async.bulk.tensor.d.shared::cluster.global.im2col” ptx instruction, but i can not understand the im2col describe in the document, and i can not find any usefull im2col example, specially the relationship with cuTensorMapEncodeIm2col.
can someone give me some im2col example or describe it more clearly?