The basic of the Google Search Ads is when you advertise on Google Search Network, your ads can show next to search results when someone searches with terms related to one of your keywords.

It means, you choose some keywords that are related to your business and when users are searching those keywords, your ads will be appeared on the first page of search result on Google.

Your ads could be highlight in the top of first page and above all websites in natural result, or on the opposite side of the organic search result, or at the bottom of screen as light.

When users see you ads, you do not pay a fee. When they click on your ads, you pay a fee. At this time the cost of credit that you should be open at first will be decreased.