idk I know about using get and post and using ajax through php and ofcourse the basics but haven't linked php myadmin through it.. I would recommend you to spend like 10 dollars and take a course on udemy.
You might have better luck searching the internet or going to a community where they focus on coding discussions ?
I've worked with PHP for a year or two, but I'm not a master or anything. You can ask me if no one's replying. c: