JavaFX is no longer included in javaSE, and it seems that the existing method may not work, so I stumbled on the introduction, so I hope it will be helpful later. Being a beginner, it's easy.
1 Open Eclipse and go to "Install New Software" from "Help" at the top of the screen.
2 Select "Add"
3 In the name field
4 Select and install e (fx) clipse.
1 Open javaFX site
2 Press "DOWNLOAD" to download the "JavaFX Mac OS X SDK" (probably choose Windows for Windows)
1 In Eclipse, go to File → New → Project → javaFX Project.
2 Enter an arbitrary project name and click Next twice.
3 Select FXML as shown in the image.### Add the downloaded javafx.
1 Right-click on the project → Build path → Add library.
2 Create a user library.
3 Add the jar in the "lib" folder in the folder you downloaded earlier as an external jar.
4 Right-click the project again → Build path → Configure build path → Add the created user library.
1 Right-click the package → Configure → Create module-info.java.
This should complete the installation. Probably.
Please let me know if you make a mistake.
I omitted the introduction of SceneBuilder because it was done by the existing method.