The communities at Thomson Reuters have been around for many years. If you have a question, it is likely that the question has already been answered. Always search first, post later.
The best way to search Communities is using the search bar in the Community header.
As you start typing, the search engine goes to work immediately, pulling matches from within the community you are in. Consider the below sample search performed in the search bar when inside the Getting Started Documentation.
Using search facets
You can expand this search to the rest of the community by clicking the Anywhere search facet, at which point other sub-facets become available to further fine-tune the search.
Click the Advanced search link at the bottom right of the search results flyout:
You will be brought to a dedicated search results view, with various filtering and sorting options