xmgr hipparcos.agr if you were in the
directory where the file is located. However, it is easier here to
start in your m67 directory, so just use xmgr and then the
File -> Open menu to navigate to your hipparcos file.
The trick to navigating with the menu is that you need to select the directory with the Filter button. In Unix, the .. that shows in a directory listing is a link to the next level up. You can double left click on that file and go up a directory in the tree. Once you have your hipparcos.agr file selected, press OK and it will load.
With that displayed, use Data -> Import and load the M67 data you
just made as a Single Set of type XY. Once it is on the screen, you can
change its form with a Plot -> Set Appearance command.
Notice that the apparent magnitudes for M67 are much fainter than the absolute magnitudes of the stars of the corresponding colors in the full catalog. Print a copy of this plot to hand in.