I’m new and need help tia x

Hello my names Rebecca I’ve only just got this. I’ve been really down about my weight since having my little boy! He’s 13 months now and it’s time I do something about it so I brought a Fitbit and thought I’d get a my fitness pal account. I weighed myself yesterday and I was 13.5 lbs😫 I wanna get back down to about 10/11. I’m 5.5 and I’m 20 years old, does anyone know what tips they can give me for loosing weight mostly from my legs tummy and tops of my arms😫 I don’t really eat much because I don’t really get the chance lol. But I’m always on my feet! I drank a lot of fizzy but I’m cutting that it as from today and have been drinking water and logging what I have ate so far. Sorry to ramble on😂 but I would really appreciate some help in what I can do to get back on track. I don’t really now how to work this my fitness pal either so the low down on that would be good to! Hope your all well x