I'm way in the beginning but I notice whether it's MT or boxing, as soon as you just do a freestyle sparring (not official sparring, just light workout at the end of the class), I am totally clueless. Even if doing pad work with a partner at faster pace, all form goes to ****. I need to slow down.
My recommendation is to not even bother trying to focus on combos yet. Focus primarily on breathing at this point. Cant speak for you, but when I was a total noob, Id still hold my breath and throw punches. I had to make a conscious effort to breathe properly.
If you aren't breathing properly, everything else you do is irrelevant. Because you can go into a fight with the best form and skill in the world, but without breathing, you'll gas within a minute and will probably get your ass kicked.
Then I'd also focus on simply maintaining distance. Using teeps, leg/body kicks, and jabs/crosses. Keep them at muay thai range (just outside of punching range, but where you can kick them), and hold that distance. Teeps are super important and should be a focal point here. You want them leaning in if they wanna land something. As they'll be off balance and open to big shots.
Then work off the leg kick. While you're holding your distance, keeping them at bay, and holding your range, you will land some leg kicks. Follow up your leg kicks with a 1-2. Then turn your distance controlling jabs into a 1-2. Then follow up your 1-2 with a leg kick. Etc.
That's really the base of muay thai. Once you have that down, slowly add in strikes to your arsenal. Elbows, knees, higher kicks, uppercuts and hooks. Then once you have the tools, then that's when you learn to start throwing them at the right time, learn to duck/move and counter, set up your power shots with smaller strikes, etc.
It's a process, and you're doing yourself a disservice trying to do it all in at once. You climb a flight of stairs one step at a time, do the same with thai.
Shouldn't take you more than 5 or 6 months to be at the point where you have the breathing down, can control distance, and have all the tools and are learning to throw proper combos.