The left pane consists of a series of filter categories that you can use to narrow down the search results. The number of available filters for each category is mentioned in a small box beside the category. View the available filters for that category (along with a short explanation for each filter) and click to apply that filter. You can also use the filter search box to search for a particular filter and Network Insight automatically shows the filters that match your search query and you can click to apply that filter. Each filter has several properties to refine the search results. When you select a filter property from one of the filters, then the selected property is highlighted in the search results.