To bookmark a thread, first navigate to a thread on the message board that you find interesting and would like to bookmark. Once viewing the thread, click the Actions drop-down menu found just above the first post of the thread, and from the menu select the Bookmark option. Once you choose the Bookmark option from the action menu, you will notice a image display in the top-left hand corner of the thread, just above the post at the top of the page. You will also notice that the Bookmark option in the action menu has now changed to read Remove Bookmark, allowing you to remove the bookmark if made by accident.
Once you have a topic bookmarked, you can access the bookmarked thread at any time using the Bookmarks button found in the menu bar at the top of the forum. This button will only appear if there are topics bookmarked to your account.