Posting an ad for a brand is draining the life out of me. Help.

Ok please bare with me I am a total novice here. I Work for a company who sell yamaha jet skis, road & dirt bikes etc. We have a store attached to the business which sells all the yamaha branded clothing for these different pursuits. We have so much stock I naively suggested we could try an amazing sellers account. I expected straightforward listings but noooo. With the yamaha brand where should I be creating this post? Should I be applying to use the brand although I’m not the brand owner? If someone could explain this process to me I would be so grateful. Today I tried to add a hoody and was met with error after error. Meanwhile my boss is asking, why sales yet?