Find WordPress Plugin
You can find the WordPress plugin in Convert's integrations page: https://www.convert.com/integrations/wordpress/ or in WordPress's plugin repository: https://wordpress.org/plugins/convert-experiments/.
Install Plugin through WordPress
Go to plugins section of WordPress:
Search for the "convert-experiments" plugin:
Press "Install Now":
Then press "Activate":
Go to your Settings and then Convert Experiences Configuration page inside WordPress and enter your Convert project ID:
Then press "Save Changes".
Install Plugin Manually
Alternatively you can install the plugin manually in your directory /wp-content/themes/<yourtheme>/header.php. Right after </title> you should paste the code of the project. You can find the project code in the Settings of your Convert Experiences project.
You can verify that Convert Experiences has been installed correctly by checking the source code of your website and find the Convert Experiments code:
If the code is not visible in the source code, you might have a Caching Plugin on that needs a refresh to make the code visible.