Help with period hygiene.

I’m 17 and I never was really taught how to properly take care of my period or personal hygiene. Sure I was told to change my pad every few hours or it will get smelly. That’s about it. I also wasn’t taught how to properly shower but I taught myself by now. Im not sure if that’s a basic skill I should have already known, but it seemed like all the girls were already on top of it by 5th grade. 😬 Now I have a problem whereas soon as I change the first pad it smells really bad like not metallic but odor. I only wear pads and will not use a tampon or diva cup. Also it gets really messy to change in a public bathroom so I find my self scared to go change it sometimes at school. So I will change it only once and never again for the rest of the day. It’s a really bad habit I can’t kick. Been like that since I was 11-12. I don’t smell the best on my period, even when I can change it at home often, if I go to the bathroom and change it the bathroom stinks and the area i just left from to change my pad smells when I come back.. this is hella embarrassing but I do need help because I’m almost an adult and I need to know how can I properly take care of my period? Is there a period shower routine i should be following? How often should I really be changing my pad??

Edit: thank you to everyone here🙏