You want to write a story where a relatively average character learns how to be an asskicking kicker of asses. Clearly they are going to need training. So first off, you need to have their weirdly hot mentor who happens to be the same age or only slightly older teach them how to throw punches, right?
Asskicking learning takes years. Literally years. Short of magic or the matrix, there is not a way around this. Fullstop.
Training someone to fight for a few weeks or a few months is still useful, technically, but only against people with even less training. The result will probably be closer to brawling than choreographed fights.
The first thing you learn in any martial art is how to stand. There is no way around this. If you do not stand properly then every move you make will be wrong. How to properly stand while fighting is not instinctive and it must be taught. There is no getting around this. Fullstop. The second thing anyone should learn is how to fall over, and the third thing how to stand up again without dropping your guard. Anyone who spends less than a full training session on this is a bad teacher, or else not really expecting their student to get in a real fight.
right now louis is drafting a tweet, checking all typos, searching for powerful literary devices to use, having it proofread by the band, correcting punctuation and deciding how many exclamation points, fullstops or question marks to use, and deciding on the perfect time to hit send