A wiki is a collaborative webpage, just like wikipedia is. The point is that everyone contributes.
The most important thing for people to contribute to is documenting their projects. If you go to Projects in the sidebar you can see a list of projects. On that page you can also create new projects. When you do, there is some basic information you need to fill in. We want to make projects have similar information, so you need to fill in the usernames of the users who participate in the project, and the tags for the skills you think are needed for the project like “programming”,“electronics” or whatever you think is appropriate. Look at other projects for examples.
About creating new regular pages: if you create a link to a non-existing page from another page, you get a “this topic doesn't exist page yet” when you click the link, but if you then edit that page by clicking the edit button on the right, you can create that page, and from then on it exists. If you want to delete a page, just edit it, and then delete all content and save it. That way the page will be completely removed.
Don't be afraid to edit pages. We can always go back in the versions of a page if you click on history, so if you make a mistake, we can always go back a version.
If you go to https://nightowl.foundationu.com/user:<yourusername> you can create a page about yourself maybe with a link to your social media or a blog, or some other description about yourself.