Founders who built your own sales process, how did you do it? I will not promote

When you first started selling your product, how did you figure out what worked and turn it into a repeatable process? What were your biggest challenges? And how did you eventually build a system that someone else, like an SDR or AE, could follow? Did you document everything yourself, hire someone experienced in sales, or bring in a GTM engineer/operator to help build the system? Would love to hear how you approached this, especially in the early stages.