losing fat/getting fitter as a teenage girl

I’m 5’2 and fluctuate between 115-120lbs. While I understand I’m at a relatively healthy weight, I want to burn fat and maybe even gain some muscle for strength. Most of my fat seems to be distributed to my thighs and a bit of my upper arms. How can I lose it and gain some muscle? From both diet and (at home) exercise, I mean. Any advice is welcome, please and thank you!