Also use batman arkham videos channel on youtube for them to watch, they wont be playing just watching, also add team guy in the story.

include this watch?v=XNskTud5V68

Because it shows the training that Bruce did to become the hero he is ad it has useful information on the loading sections such as, "A warrior does not foolishly try to take on 10 opponents like a stubborn ox. He escapes, opens the distance, and focuses on defeating one opponent at a time." Make sure they watch this first before they officially start watching the Arkham series.

ps. you may include arkham vr but do it after arkham city and before knight you know in between. (Optional)

Pss. You may also do Batman Arkham origins black gate after Bat man arkham origins. (Optional)

Psss. The dlc Cold cold heart, Harley Quinn's revenge, and The the arkham kight DLC story packs you need to. do first before arkham knight campaign show the batgirl dlc first then, then the rest of the story packs after the Arkham knight story. Because the showing the Harley quinn arkham knight story pack before the main story might reveal spoilers. (Mandatory)