First Watch Batman: The Animated Series
Then watch the cult classic Mask Of The Phantasm
After that enjoy another DCAU Film, Batman: SubZero
Then cross over to Superman: The Animated Series and watch the the three part special World’s Finest eps AKA ‘The Batman Superman Movie” on released video
Then start on the The New Batman Adventures
After ending that watch Batman: Mystery of the Batwoman
Then watch Justice League the way into Justice League: Unlimited and skip ep “Epilogue”
Then watch Batman Beyond
Then for the final DCAU film on this list. Watch The Return of Joker
After that go back and watch The episode “Epilogue”