When you build muscle do you lose the fat at the present moment you’re building muscle, afterwards or before. How does that whole muscle/fat conversion play into effect?

like after lifting or running. not really weight gainers though, i want to be really lean

I see many skinny guys who weight lift in foot ball for 1 year, and they say they cant build muscle

I seen some guys who weight lift alot but still really skinny why?

I mean if they can lift more, there had to be some muscle up grade why? What does their muscle do then?

I just want to start working out to lose some weight and gain some muscle. What supplements are best for this? Like anything that will boost metabolism, lessen the burning in muscles while working out, anything that will build muscle? Just need a few tips on it because I’m new to this. Thanks alot!

Im 16 and have been getting kind of chubby lately. I want to know whether i should lift weights and try to build muscle or whether i should just focus on losing fat by running and stuff. I guess im trying to ask if building muscle burns fat. Also, im 5ft 9 so would lifting damage my growth?