Unfortunately there is no English manual.
But just drag the 4:3 scene to the MediaPool, go to the 16:9 target project, and drag the scene from the MediaPool to the 16:9 project. It will be converted to 16:9 with black borders and those can be removed with the Aspector.
Note: My help in this forum is also supported by advertising, which is visible for all Forum members at this point. Thank you for your understanding!