I suggest using one of the articles from the 'Spotlight' menu as a template. Create a new article by copying the Wiki code from one of those.
There are two views for editing: the 'Visual editor' allows you to edit the article without seeing it in code. The 'Source editing' is the Wiki code. There is a drop down menu at the top for changing between the two.
(This is the same guy who created languages for Game of Thrones, the Marvel Cinematic Universe and others. He's basically the Bob Marley of conlanging and also the go-to conlanger for major film and TV projects today.)