the implementation of EcoBuilderToday is using the Blog application categories as secondary navigation. This is applicable for all three post threads.
In order to manage them, you need to manage the categories of each of the three blog applications that are the backbone of your system.
These steps are applicable for your custom implementation only:
1. Log in to the Public site with an account that can administrate the blog application instances. An Architect, Builder or Manager role account will most probably do the job.
2. Click on the Admin tab of the primary site navigation
3. Here in the second navigation you can see the three blog instances "Posts", Green projects" and "Dave views"
4. Select the Settings tab of the "Posts thread administration"
5. Click on a category in the grid to manage it or create new categories. The changes will be immediately applied
6. Do the same for the other two blog threads by selecting them in the secondary navigation
7. You are done
Have in mind that each horizontal navigation has its limitations in width.