Mainly by free association - clicking on links you come across that look interesting. Each page also has a search box at the bottom - you can type in text, and search the entire wiki. And if you click on the title of a page, you'll get a list of pages that link to it. ToothyWiki uses this feature for additional ways of organising pages: see CategoryCategory.
RecentChanges is also a good way of finding pages - you can see what people have been arguing over most ^-^
How do I write stuff?
Just click on the "edit text" link at the bottom of the page you want to edit and write what you want to say, exactly like you would in an email. If you write two or more capitalised words with no spaces between them, they'll turn into a link to a page of that name. Go try it out in the SandBox right now, if you like!
The simplest way to find out how to do something is to find a place where someone else has already done it, click on "edit this page" and see what they've typed. You can also check out the work-in-progress wiki documentation.
If you're going to be writing lots of stuff and coming back regularly, you might like to [register] as a new ToothyWiki user. This will mean the nickname you enter will get used in RecentChanges instead of your IP address, and ToothyWiki will remember your [preferences]. You might also like to set a password and remember your user ID number (displayed at the top of every page, next to your nickname, when you are logged in), so that you can log out and log in on different machines (gruesome details here.)
If it's a general question, try the QuestionBox. If the question is about a particular page, ask it on that page, not this one. Do have a read around; you may find that your question has already been answered. ToothyWikiInternals/Documentation describes the basics and ToothyWikiInternals has a lot of documentation on everything else.
Questions to specific people
If it's not part of an ongoing discussion, their homepage is probably the best place to ask.
Questions about anything else
Find the page closest in subject to the thing you're asking about and ask there. If you've looked and are certain there isn't one close enough: if the question is a quick one-off thing, ask on your own homepage or on QuestionBox. If it's on a subject of ongoing interest that you think deserves an entire page for lengthy discussion - make one! (see next section)
Given that the ToothyWiki community life is (currently) almost completely oriented around the RecentChanges page, your question is as easy to spot on any page as on any other. So for maximum politeness, asking it on your own HomePage? if it's a one-off or on a page intended for discussion of the subject if it's not works quite well. Filling in the "Summary:" box with a helpful summary of the question helps a lot, especially if your question is to a specific person (or kind of person)
What are all these weird blue question marks?
If you run several CapitalisedWords together, you'll make a link to a page of that name. The MysteriousBlueQuestionMark? appears if no-one's written that page yet. If you click on it, you'll go straight to the editor - you can be the one to write it! This is also a good way to make new pages; write the link first, then click the blue question mark and fill in the text. To make a link to a page with only one capital letter, enclose it in double square brackets: if you type [[Go]] you can make a link to the page called Go.
Before starting a new page, though, it's usually worth a look around to see if someone else has already written one on the subject that you could edit instead. While there's no set topic, this fact is not intended to be a general invitation for the creation of utterly spurious pages. Please use your common sense :) See LeafPage and WikiEtiquette for more discussion.
This is stupid. Why would it ever work?
I don't know. It does at the [WikiWikiWeb] - there's an excellent discussion at [WhyWikiWorks]. But I don't know if this particular Wiki will work yet. That's up to you.
It probably is working, but in the interests of fair and balanced reporting, I link you to its antithesis: [The Register]
There are a bunch of legal announcements and disclaimers EU-based websites ought to have. In the interests of maintaining a SinglePointOfTruth? while keeping these prominent, they get placed at the bottom of the main page of the wiki.