Here's how to integrate your OptiMonk account on your Drupal site.
1. Login to your Drupal Admin dashboard.
2. Go to Structure -> Block layout -> Custom block library and click on the Add custom block button to create your custom block.
4. Go to the Block layout page and click on the Place block button at the Footer first section and select your custom block then Save.
Congratulations, you're all set! Please note, if you would like to use cart segmentation with Drupal, then you have to develop it. More information here.