Hi, David,
2. Find the login in button up in the top right hand corner and get logged in (If you've already done this, then ignore sets 1 and 2.)
3. Click on "communities" which is located in the brown strip at the top of the page
4. Click on "All Communities."
4. Scroll to the bottom of the opening page of the list of communities (there are lots of them).
5. At the bottom of the page, click on the number 5.
6. Scroll up the list to "Tools & Parts: Buy, Sell, Exchange." Click to enter the community.
7. There should be a link that guides you through the joining up process.
8. Post to the community.
8. That's all there is to it!!!
Maybe someone has a quicker easier way, but the above should at least get you to the place that you can join the community.