To install WordPress into your DirectAdmin navigate to
Control Panel > Advanced Features > WordPress Manager
After clicking on WordPress Manager you will be prompted with the WordPress Manager tool.
You will be able to directly install WordPress to your site by clicking Install on the right side of your desired Domain.
You will be prompted with the WordPress installation directory and provided a text input box to fill in your requested WordPress Installation name.
Note: There are also some additional settings that advanced users may make use of such as Administrator Settings.
Click Create