Here's Suujin's tutorial~
http://www.mangago.me/home/album/84934/
If you go to the manga/webtoon's page, you'll see a little flag icon hanging out on the left side of the screen. Click that and press the 'upload' button, share the link to the downloadable version (on imgur or a drive I guess) with the chapter number. At least... that's how it is in theory. Today I tried to upload a manga I cleaned/translated and its been 9 hours and the admins bless them still haven't uploaded it :,). Also, hoping someone else responds because can we even upload a new version of a chapter?? Is that allowed??
You can upload a new version ONLY if you get permission from the person who uploaded the original one. You should talk to them and they'll tell you how to go about it
How does one upload on this? Recently a uploaded uploaded some chapters to Smurf’s World but one of the chapters was uncensored and some of the people in the comments wanted the uncensored version, I have that version but I don’t know how to upload it