Do you know when to use “mně” “mě”?

I am native czech speaker. But lately I’ve discovered that loads of people from czechia don’t know when to use “mně” or “mě”.

E.g

“Dnes mně přinesli oběd” (Today they brought me lunch)

“To mě zajimá” (That interests me)

And if you know where to use which I am wondering how did you learn it?

Because am capable of explanation to czech native speaker and I have no idea how would i explain usage to someone learning czech

Thanks 😄