People are turning to audio and visuals when it comes to technical subjects. However, you should consider doing an ebook first and turning it into an audiobook through a resource like Audible's ACX platform. You can hire a producer either through a royalty share program, so you don't have to shell out upfront cash, or you can do a pay-per-hour hire as well.
eBay: eBay is one of the most popular websites in the world, period. That means it’s a great way to attract lots of eyeballs to your unwanted items, fast. Initially designed as an auction site for DIY sellers, it’s now primarily a venue for fixed-price (though often heavily discounted) sales by professional merchants. Still, as long as you include high-quality photographs and thorough descriptions in your product listings, you can likely break through the noise. eBay’s fee schedule is complex, but as a general rule, expect to lose 10% of your final selling price to the site’s commission.
Find your niche partners, collaborators, and champions: As you’re creating your course, look for notable people who are also creating content in the space. Look at how their businesses operate and incorporate that into your own plan. You can also reach out to any influencers and make them affiliates for your own course. This way, they’ll be incentivized to share your content with their own audiences (which can be a major way to generate your first sales—it helps if you're using one of the best CRMs for small business—and start building your own community!)