Make sure you're signed in and go to https://inkstone.webnovel.com/novels/dashboard which can be accessed by hitting the 'Create' button at the top of your screen while on WebNovel.
You'll need to go to Novels on the far left of screen under Dashboard, and hit '+ Create Novel' over on the top right.
From there you'll add a story cover (which has to fit exactly into the perimeters of 600x800pixels, no more than 5mb, and jpg format. You can skip this part for now.)
Then you'll need a story name, no more than 200 characters are allowed. I recommend something unique and something that correlates to your story. You can also put in an abbreviation under it, which is like a short-name. My story is called Embrace the Ether, so my abbreviation I set was 'ETE'. You get it?
You can select who your target demographic is, from male to female. I imagine this helps target genres like fantasy, romance, and violence. Etc etc.
Go through and accurately select your tags and genres, don't wrongfully select one because it may bring in a smaller audience or may not be well received if it's not what was advertised. So don't mark a war-fantasy story as Romance, unless there is a very heavy emphasis on it.
You'll need a synopsis after that. A synopsis is like a description or summary or the story without giving away any spoilers or twists. Basically it's what you'd expect to be written on the back of a physical book. A preview, pretty much.
You'll hit Create once you're done. Before you can publicly release it, though, you'll need to add a chapter, whether it's a chapter 1, a prologue, or even just an auxiliary chapter to act as a stand-in placeholder.
I recommend a daily release schedule for the first while, to help you build a larger audience quicker.