Select the Shortcuts function from the Preferences menu. The Shortcut Keys dialog will appear.
In the Select a macro list, left click on the Arcs:3 Entities function.
Click on the Create Shortcut button. The Assign Shortcut dialog will appear.
Hold the Ctrl key on the keyboard and press G.
The input field will now have Ctrl + G in it.
Click on the OK button. This will close the Assign Shortcut dialog and return to the Shortcut Keys dialog.
In the Assigned shortcuts field it will now have Ctrl+G listed in it.
Click OK to create the shortcut and close the Shortcut Keys dialog.
When the Ctrl key is held down and G key is pressed, the 3 Entities function from the Arcs menu will be activated.