The sidebar runs down the right side of the page. Starting at the top, you first come to the page name and a short introduction, or just the word "Next". Clicking on "Next" takes you back in time through the posts on the board. "Previous" does exactly the opposite. (To get back to the main page, click on the page title.)
Under "Next" is "Recently", which is a list of the most recent posts, and "Last comments" which is a list of the most recent comments on the blog that you're viewing. IOW, if you want to see the most recent posts/comments on ALL blogs you need to be sure you're on the main "Timbuk3" page. Again, clicking on the blog name will take you back to the main page of that blog, clicking on the tab takes you to the main page of the individual blog. (Confused, yet? Try it. It's not too bad.)
Next you'll see a calendar. Use the calendar links to call up posts by day of the month. "Archives" (a little lower down) will call up months, and a corresponding calendar.
I haven't tried the "search", yet, but it should be self-explanatory. Enter a word or poster's name, and search for it. See what happens.
Beneath "Search" is "Categories", where you'll see links that do much the same thing as the tabs at the top. These seem less useful to me, and I'll get rid of them if I figure out how, unless someone REALLY wants them.
Next is "Archive" which is already referenced above, but it allows you to change months to see old posts.
Then, at least for now, there's "Skins". Click on each skin and you can change the look of the page to suit your own tastes. The default skin is "custom" if you get lost.
Below skins is "Linkblog". That's where this post will always reside so it's easier to find. See how this works? If you post something that should be "up front forever", like a FAQ or a link to a favorite blog (there will be a blogroll category if it's not already there) this is where it goes and this is where to look for it. These things are posted through the "links" tab. More on that, later.
Below that is "Misc". If you see "Admin", you can post a blog. Click on it and you're taken to a page that looks entirely different. I'll explain posting, later. Or, you might see "register". I think you know what that's for. "Profile" takes you to your individual profile. I'll let you deal with that, but I HIGHLY recommend you uncheck the box that says "Check this to receive a notification whenever one of your posts receives comments, trackbacks, etc" unless you want a full email box. "Subscribe" also means you'll get an email notification. I recommend against this because with any luck this site will get busier and your email box will fill up quick. Then, of course, there's a place to log out.
Finally, there's the RSS links. There are 4 RSS feeds from this site. Click on the "What is RSS?" link if you want to learn more, but basically you can set up an RSS reader to update with now posts and comments from this site. Most readers support "Atom", by now.