For 오, just say "Oh" without the w-sound at the end.
어 is like a mix of 오 and 아. Make your mouth round as if you're going to say "Oh" and say "Ah" instead. If you do it correctly you'd pronounce something like the O in "on".
As for 에 and 애, check out this video:
May 21, 2016
Still haven’t found your answers?
Write down your questions and let the native speakers help you!