I am absolutely awful at restringing my guitars and I have no idea why.

Every time it comes to restring my guitars due to broken/shitty sounding strings I manage to mess it up. I restrung my Epiphone Dot a few days ago for the first time and now like 3 of the strings have this metallic ringing noise by the bridge when they ring out (and it's not just the "fresh strings metallic noise" either, I've played it for quite a few hours and nothing changed) and the top two strings buzz.

This always happened on my old (terrible) acoustic too, the top two strings would constantly buzz. I honestly have no idea what I'm doing wrong - I put the string through the bridge, put it through the hole in the tuning peg thing like every tutorial says to, then turn the peg until it's tight and tuned, then clip the excess off.

Please help me before I go clinically insane.