first make sure you're comfortable enough being physically close that you can correct each other when something's uncomfortable. like moving the other's hand to a different spot when kissing, or changing positions a little while sitting on the lap, or straight out telling that something hurts without being afraid of hurting the other's emotions.
after that, it's all talk. and talk. and more talk.
with a whole lot of doing as well. but never forgetting to talk.
girls can be both curious and opinionated. try to give her some freedom if you don't have any good ideas of your own.
good sex is only created through cooperation. there is nothing you can do completely on your own to make someone feel good.
you could try of course, but you'd risk making her feel bad as well.
as for how female genitals work...
defying your dysphoria would give a whole lot of answers.
if you don't want to, i'll just mention the manga title "futari ecchi".
it's rather informative. definitely something i'd leave laying around when kids grow into teenagers, if only i owned volumes in english.
only drawback would be that it's called manga sutra in english. that doesn't reflect the content at all.