I have not fully watched the video and I myself do not compile for Arm processor or linux.
Edit: I watched it, he does not demonstrate installing the Arm compiler. He just shows how to install cross compilers in common.
You must understand what he does in the video and possibly adjust this for your use case or watch another video.
Also watch out for global environment variables which could interfere, if you had previous and different installations.
Somewhere I have read the recommendation to use trunk for crosscompiling to other processors, because this is most up to date.
I do not know, if this is true for your use case.