Click on the Index Tab to display the Index Tab Page.
Index Tab Page
Type a keyword into the Find Field or select one from the list. As you type, the topic associated with that keyword is displayed live in the Topics Found Column. Words that appear higher in the column are the best matches.
When multiple topics use the same keyword, a right-click on the word displays a pop-up list. There are significant instances of the keyword that you are looking for in these "pop-up topics".
Click once on a keyword, or on any pop-up list item to display the associated topic in the Topic Pane.