This is the way that I added the ads to my sites.
Step 1 log on to your WordPress site with your admin account.
Navigate to plugins and click Add New
Next to Plugins Click Add New
In the search box type in WP Advertize it and hit the enter key.
WP Advertize it should be your first hit click install now.
Then click on installed plugins
Find WP Advertize It and click settings.
Click on Add Block as many times as you want. I added two types of Ad blocks to my code. Your needs may differ.
The next step is to go to your favorite advertising provider. I recommend Chitika. Open another tab in your favorite browser as you will need to come back to this page.
The link for Chitika is https://publishers.chitika.com/login
Sign up with them and get your add code.To do this go to their site.
Click here to apply. Add your email and press go. It will ask you a few questions but it does not take long to set up an account.
Click on ads get code.
Select the format that you want your ads to appear in.
I went with the recommended on and the Rectangle wide but whatever you decide on select that and click get code.
Copy the code you see in the shaded section and go back to the other tab.
Here paste the code from both banner sizes into both ad blocks or however many you have.
Scroll down to the placements section here you can decide where on the page you want your ads to appear. You might want to do some experimenting to see what looks best on your site. These are the settings I used on this site.
When you have finished click save changes view your site and see if you are happy with the placement of ads. If not experiment a bit until you are happy.
End of procedure.