If you were to ask a naturally muscular
guy or some
random big
guy at your local
gym how to build muscle and put some meat on your bones to be more like them, you'll highly likely to just hear some generic advice that doesn't help you.
If you want to truly, finally transform your physique completely to overcome your potentially poor muscle gain genetics and leave your hardgainer status behind for good (which is 100 % possible no matter what others may have wrongly told you), asking advice on bodybuilding from any
random personal trainer or some big
guy at the
gym who likely has better muscle gain genetics than you (or unnatural help in some cases if we're being honest) isn't the smartest course of action because chances are they don't understand how you can fully transform your physique as they weren't a hardgainer themselves in the first place.