Seems pretty straight forward for X and Y. I understand how he measures Z, but not sure why he chose the Haimer to be tool 1, or how this interacts with the tool table. I'm old hat and use a master tool, labelled 0, to set a zero for measuring tools for the tool table, and to set the work zero in Z. Modern thinking tends to use the spindle nose as a reference, but that can be a PITA to see what's going on. And in some applicastions is too large to be able to set the work zero in Z.
Andrew