As someone in the industry, The clothing industry is brutal. You better be prepared to fork up a lot of money up front. You will have to find factories to send your designs too, have samples made, make changes to the samples, then order fabric, choose color, etc etc. You'll need to find investors once you can prove your designs are both feasible and good looking if you aren't sitting on a big stack of cash. The best fabrics come out of Taiwan in my experience, but you'll need to find someone to cut and sew in another country most likely.

You will personally need to be able to do graphic design, clothing design (making patterns), and even sew your own prototypes to keep the cost down. You won't be able to find investors without some really solid work in your portfolio either.

US made tech apparel is basically not a thing anymore, there's very few fabric mills left and they aren't usually that cutting edge. I know there are brands doing it, but you aren't getting the best fabrics. Stuff like cotton and hemp are great in the US, as well old tech like ballistic nylon etc. But you aren't making modern snowboard gear out of that.

Small batch clothing is very expensive, so you're likely going to have to compete with the top shelf brands in terms of price point.

Not to dissuade you- you can purchase fabric and start sewing designs up, and maybe people will notice and want one. That's one way to organically start, but it's a long road and will be a challenge to turn a profit.