Place your cursor at the very start of the page and insert a template from the menu. Search for Infobox-Resources. The template will give you additional information on how to populate it. Replace this text with a very brief overview of the Resource using simple language. The intent is to give readers a clear and concise overview of what the Resource is. If they want further information they will continue reading into the upcoming sections which go into greater depth. Feel free to inspect other pages in Category:Resources for examples.
If any sections of this template do not apply to the page you're creating, or you don't want to create the full page, simply delete the unused sections.
Replace the text in this section with a description of the Resource in as much detail as you wish. You can also add further subsections within the description section, starting with the "sub-heading 1" text style.
As you write, think about which Concepts, People, Projects, and other Resources you're mentioning that would also be useful to have pages on within the Wiki. If you believe it would be useful for them to have a page, you should format them as an intra-wiki link the first time they appear in the text. For example this is the first time I mention Game B. If I continue writing and eventually mention Game B again, it should not be a link.
The final section, References, will be automatically generated with all of the citations you use in your writing. Ideally, all of the information you use would be cited from a source, like so. Be especially careful to cite the sources of quotes. Blockquotes (selected from the list of text styles) like this one can save you a lot of effort while making the source of the information very clear:
"The mission of the Game B Wiki is to connect people attempting to play Game B with the information that they find most useful."
Once you're done with the page, use the menu to add the Category "Resources".