IT'S SO EASY
Your ideal search terms
The booking of the desired search terms (keywords) takes place at Google with an auction procedure and depends on the desired position in the search result. In doing so, you determine what is best for you by clicking on your preferred keyword for the targeted position.
If someone searches for "your" search terms, your ad appears at the location of the search result that matches your bid: The ad with the highest bid is shown first, with the second highest shown next, and so on.