In the video
I've posted is a description about the files you need for GID to work.
- Place the table via editor and go to preview
- Lock the table with GID and place it where you want
- Click on "Copy Item to Clipboard" and paste that code in your location1.sqf and save it
- go back to the editor, delete the table placed by editor (not the entry in location1.sqf) and place the items you want to put on the table nearby
- lock and positioning the items with GID like the table in step #1
- Copy to Clipboard and insert the items in your location1.sqf like in step #1
- delete the items you inserted via editor
After you placed an item via editor, moved it via GID and copied the GID entry to your location1.sqf GID is creating a second table at the position you moved it via GID and the origin table placed with the Arma editor set back to its former position. So you can delete every item placed by editor after you created an GID entry in your location1.sqf cause this doubles every item.