If you run through that guide I think the intended result is that "Alt-C" is going to be your copypaste. E.g. the keys work in the Mac order: CTRL / OPT (ALT) / COMMAND instead of the Windows order (CTRL / WINDOWS / ALT). So using Alt-C should trigger Copy, matching Mac-user muscle memory.

Perhaps PyCharm is set to Windows keymappings or such?