I want to learn bios modding

All experts please help with learning how can modify or edit any bios. a week ago I received dell Precision 3520 for bios password unlock I try to unlock myself, I download bios from dell’s site replace the bios region and clean me region but my bios did not work then someone gives me bios for my laptop dell Precision 3520 and its just work fine. I want to know what he does with bios and his bios work. please help me.

I give link bios here.
my test bios