Welcome to 3FC =)
It can take a few days to get used to things around here, but the forums are set up into sections, and then area, and subsections.
The big Sections are Announcements, Success Stories, Support, Diet Central, Maintainers, Fitness, and Food.
Within those sections are areas that are a little more specific to what we're looking for. If we're checking recipes, we look under Food and see there's an area "Food Talk and Fabulous Finds" which has an area for recipes.
Or if we're looking to find out about people following a certain named diet program, we can check under Diet Central for all sorts of things from Atkins to Weight Watchers.
Take your time as you look around. Post where you're comfortable, you'll get used to it and be able to return to sections that you enjoy.