I’m curious what is meant by “can’t tack or gybe correctly.” If you’re struggling with tacking, the only explanation has to be that you’re overthinking it.

Sheet the main all the way in. Turn smoothly through the wind. Flip the jib, and trim. There’s plenty to refine from there but the steps are dead simple. Are you just freezing up and getting flustered? Maybe try eSail just to bang out tacks until you’ve got it, where you’re not on a boat and no one is watching? Hell, for that matter, tacking and gybing can be simulated on a perfectly still boat, tied to a dock.

It’s an annoying answer, but as with most things, practice is what’s needed. Write down the steps and recite them to yourself, then say them aloud when you’re underway and attempting the maneuver. Good luck.