I know a guy who does this, i helped him with the tech side so I have a pretty good grasp of how it's done.
casting women = escorts, cam girls, strippers, sexyjobs.com, eastern europe, ocmodeling.com, hussiemodels.com, and many more adult model casting agencies. Bigger agencies will at first reject you if you have 0 content on your site so you'll need to get rolling with amateur girls. Not surprisingly lots of johns try to book porn star models for escorting which is something they don't like due to the risk and no fame benefit.
equipment = some high end sony camera that was about $3,0000, you could probably get by with a panasonic GH4, a pair of cheap 700w studio lights available on amazon
website = elevatedx.com which is like wordpress for adult sites, lets you setup membership, billing, trials, etc. Used by many big sites. Their server/hosting service is way overpriced, go with vultr.com or digitalocean.com instead
payments/merchant account = ccbill.com is what he uses, oldest and most stable with weekly payments but they charge a higher fee than most. The upside is 0 headaches and it's a trusted name among the few remaining people who pay for porn and is easy to setup with just about any website. There are other options but no sense in fiddling around to say 3% on fees
marketing = uploading clips to all the free porn tube sites, subreddits, forums, and making webm's to post on 4chan's /gif/. These places don't send much sales directly since they are 99% freeloaders but people searching through google for keywords will find them and he gets a lot of sales that way. A clip hosted on pornhub is 500% more likely to show up on the first page than if you hosted that video on your own site. He uses semrush to evaluate the big sites like pornhub, xvideos, etc and then filters by keywords for which ones he should use.