Creatine is a waste of money for most people.
If the primary goal is to burn fat then as with any goal, diet is key. Walking and swimming will help speed up the process.
Muscle building requires weights, using the right technique, tempo, eating lots and sleeping. You can't just go to the gym once a week and have a protein shake. It's more like four times a week and eating five or six meals a day.
I did this over a year ago. Stopped eating junk, walked five miles three or four times a week till I got the fat off, then joined the gym and was told I needed to eat 3500 calories a day lol
Six months later I started to look great, then covid.
You can't really lose fat without losing muscle, and you can't gain muscle without gaining a little fat.
Best thing is to get some stats up. Weight, height, age and body fat percentage if possible.
Remember, if you want to gain muscle you want your weight to go up not down.