In the screenshot you attached, I found you are using the Web Recorder dialog to run your Test Case. This is a mistake.
You are likely to encounter failures for importing org.openqa.selenium.* classes, as the Web Recorder dialog is designed specifically for letting Katalon Studio to generate codes which simulate Web UI operation. Web Recorder is not a tool for general purpose programming. I suppose that the classpath of the Web Recorder dialog is not configured to include the jar of the WebDriver. Therefore, in the Web Recorder dialog, you are possibly not granted with immediate reference to the org.openqa.selenium.* classes.