what's the practical way to reddit work?

lots of subs run a weekly self-promo or "share your project" thread, that's where a link is actually welcome. also some subs auto-remove posts from accounts under a certain karma or age, so the warm-up period isn't just about manners, your posts might literally not show.

if you mean reddit for marketing: pick 3-4 subreddits where your customers already ask questions, read the rules (a lot of them ban self-promo outright), and just answer stuff for a few weeks with no links. once people recognise your username you can mention what you do when it's actually relevant. the trap is showing up with a brand new account and posting your link. that gets removed or downvoted fast and the account gets flagged.