How to add realtek ameba core files:
You can reference below link to get start: http://www.amebaiot.com/ameba-arduino-getting-started/
Or you can follow steps to setup.
We also suggest to enable "Show verbose output" options on "compilation" and "upload" in Preference.
Open "Device Manager" in "Tolls" -> "Board" -> "Board Manager". Wait for IDE update core configuration. Scroll down the menu, you will see Realtek Ameba in the list. Press "Install" at the right side.
Select Ameba in "Tools" -> "Board" -> "Ameba Arduino". Now you are able to develop Arduino code and upload image onto Ameba.