To use effectively and find what is beneficial please read on.
First
You can use the index tab on the left and type how for example, see image below
Second
You can use the search tab to either search for one word or more, as follows
To search for one word just type it in the text box and click on List topics, then notice the topics listed, and once you double click a topic, the topic will open withe the word searched for highlighted.
To search for a combination of words, write the words between quotation marks and use the + between the words as follows: "sales+page", then the topics are listed, and when your selected topic is opened, you will notice both words searched for are highlighted.
You can also use the operators AND OR NEAR NOT as shown below, by click on the arrow
The Favorites tab is great for saving your selected topics for later use, once you have identified a topic that you want to get back to, just click the favorite tab and then click on Add at the bottom.
Third
Use the Content tab and click on the + to open up the contents and then double click any of the topics, to see its contents.