I exactly followed the instruction for compiling on linux. I opened a terminal inside darknet-master (cloned repository?) and ran:
./build.sh
But when I run training command inside "darknet-master/build/darknet/x64" get the following error:

Why isnt darknet working in "darknet-master/build/darknet/x64" ?
I appreciate any help
You have to have the darknet executable in the same directory to have it running. This should be in the darknet-master/ directory if you made it from the Makefile.
@inafi That was it. It worked. tnx
@inafi
Sorry but I am new and not familiar with the darknet, however I red the guide still it is confusing to me
Now the problem is that I want to see the mAP & Loss-chart during training on remote server
I set OPENCV=1 in the make file inside darknet-master, then I execute "make" command in the terminal at the same directory. But still when I run the training OpenCV isn't used.

@inafi should I copy "makefile" or any other files to the "darknet-master/build/darknet/x64" as well?
You have to use whatever darknet executable that you made with Opencv and replace the one in your directory with that.
Most helpful comment
You have to have the darknet executable in the same directory to have it running. This should be in the darknet-master/ directory if you made it from the Makefile.