Direct answer: Eagle’s manual procedure is: press and release the receiver program button, wait for the LED to turn red, then press the desired remote button twice. The LED should flash and return to green.
Adding more remotes
Repeat the same sequence for each additional remote. Eagle also states that holding the receiver program button for about eight seconds deletes all enrolled remotes, so do not hold it down when you only intend to add one.
Source checked: Eagle operator manual with EG650 programming procedure