How to sell Digital Products?

Hi! I’m currently trying selling digital products but it doesn’t seem to work like anybody else. They said na after a day, you’ll get something kahit 3-digit sales pa lang but 0 talaga sakin. Is there anyone who can teach me how to do this properly?

I didn’t buy any course because I’m too broke for that (I’m a college student) but bought the 399 15M+ products you can resell + one with a file of strategies. I did the fb marketing by joining groups and posting products but didn’t work out.

I’m just really eager to have passive income as a student because of some financial issues. It’d be nice to provide for myself without relying to my parents, right?

Also, do you guys know any passive income I can do as a college student? Your suggestions and advice will be very much appreciated. Thank you!