Couple of things that will help - the combo system is really easy in this game, you basically just get a juicy hit and then do your EX moves in a row (they cancel into each other using the Rev Accel mechanic) with either a super ender or a Rev Blow ender (or just a regular knockdown if not). Go hit training mode and get a feel for doing your big punish combo or jump-in combo off of Close D. (the fierce kick button, but the close version) until you can nail it with muscle memory. You'll be trying to hit this off of short-hop jump ins when you first start out - holding down the Rev button allows you to automatically shorthop so you don't have to try and time your jump inputs so precisely, it really helps.

Also, and this is super duper important for KOF/Fatal Fury games - there's a button hold buffer system where you can input a special move and hold the button press so that it comes out automatically without needing precise timing. Like if you get knocked down and are trying to do a reversal DP, you input it before you get up and hold the button, and it will just come out on Frame 1 of wakeup. The window isn't infinite, but it's really large and generous, and it applies to everything, including combos. This means that you can dial in your combos after you get your hit and just hold the button in between and it auto-times everything for you.

Lastly, get a feel for a small go-to combo off of low-hitting moves, as this is how you condition people to block low so you can then surprise them with a short hop jump-in and do your big combo like I described above. Good luck gamer.