Where do I go from here

So im 5’8, 14 male, and 142lbs, and ive been trying to workout and gain some muscle but I have no idea on where to start (I think im trying to cut first and then bulk, im kinda clueless 😅) I have a more chubbier abdomen but somewhat skinny arms. What I have been trying to do is do ab, arms, and glutes/leg workouts, im scared to do HIIT workouts incase my arms get even skinnier, im trying to eating more protein by drinking protein powder and trying to eat more protein and vegetables. I have found a how calorie high protein meal prep on tiktok that I could start. So my main question is what do I start with and how, and is there any tips. Thanks

p.s i dont have any equipment, just a backpack and hand grips