Looking for a mentor so to speak.

Starting a gymwear brand from absolutely nothing — looking for someone experienced to learn from
I’m starting a gymwear brand called Final Boss Apparel.
The entire concept is built around perseverance, discipline, and the idea that your biggest enemy is the version of yourself that wants to quit.
I’ve got the brand name, social media, logo direction, and a ton of design ideas already. I’ve even started working with Printify/Shopify, but I’m realizing pretty quickly that I don’t know enough about the apparel side of the business yet.
I’m specifically looking for someone who has experience with clothing brands, gymwear, printing, manufacturing, garment design, or product development who wouldn’t mind sharing some knowledge and potentially building alongside me if we work well together.
I’m not looking for someone to work for free. I don’t have money to hire anyone right now, and I don’t want to waste anyone’s time. I’m looking for someone who enjoys building things and might be interested in mentoring someone at the very beginning of the journey, with the possibility of seeing where it goes.
I’m willing to put in the work. I just don’t want to spend the next year learning every lesson the hard way when there are people who have already done it.
If you’ve built a clothing brand before, I’d genuinely love to hear how you started and what you wish you knew at the beginning.

I grew up blue collar and I’m learning pretty quick that this is not as easy as starting a pressure washing company and going door to door.
I absolutely want to do all the work and I’ve loved the process so far. Where I’ve ran into issues is after linking the online stores etc. I can’t figure out how to fit the designs I’ve created onto a shirt based off the online dimensions given. I want the design to take up the entire back side but all the available options give you less than half the space to work with.

Obviously I’m biased but it’s been a lot of fun and I think this has a lot of potential. I have a ton of designs. Multiple spin off versions. Theres the Original FBapperal, FB midnight edition, FB before dawn editions, and the list goes on.

If anyone’s willing to sit down and give me some time, maybe an online call etc. I’d greatly appreciate it.