Please check on the bottom of the lantern for an area that you can twist to open. If this process fails, please call manufacturer for copy of product manual. Thank you.
Please understand that you are talking to regular people who offer advice on FixYa forum, not to Coleman.
You could check with your local historical societies or museums.
I found that bashing it with a hammer numerous times helps to alleviate some of the frustration plus what does it hurt? Not like the damn thing was working anyway