Gocv installation error

I was following the installation instructions here: https://gocv.io/getting-started/windows/

But there is an error…
I also tried " go get “gocv.io/x/gocv”"
That also gives the same error:

# gocv.io/x/gocv
In file included from calib3d.cpp:1:
calib3d.h:5:10: fatal error: opencv2/opencv.hpp: No such file or directory
    5 | #include <opencv2/opencv.hpp>
      |          ^~~~~~~~~~~~~~~~~~~~
compilation terminated.

Please help me install gocv. I’m at a loss.

Did you follow the instructions precisely? Did you run

go get -u -d gocv.io/x/gocv


I try to make all tutorial, but I had problem with mingw