server(can be called anything), placing your server jar inside it, and if necessary, filling out the eula.
ADD CONFIGURATION, usually at least. If you've used Gradle on the project, any tasks you've ran will also appear there. That's irrelevant though, the point is there's a button there, and you need to click it. Upon doing so, either a window will open up, or a dropdown.
JAR Applicationfrom the dropdown.
Path to JAR:, and
Working directory:with their corresponding values. That is, path to jar, being the path of your server jar, and working directory, being the path of the directory your server jar is contained in (will be
serverif you followed this guide exactly). Here's mine:
APPLY, and then
OK. Select your newly made configuration in the top right drop down (if it wasn't automatically selected) and then press