I would like to start off by saying despite how you feel about the latest big screen adaptation of Batman v Superman, the importance of Darkseid to the DCCU (DC Cinematic Universe) is unquestionable.
A couple problems occur for DC in this, is that most people outside of the comic fandom don't know who Darkseid and the New Gods are.Even with the newly deleted scene of Steppenwolf and the mother boxes as seen below, this still did little to explain what is going on or much excitement.
The second problem is that Darkseid resemblance to both Apocalypse and Thanos. Although Darkseid came first in creation, Marvel Studios were the first to bring Thanos to the big screen with their post credit scene and the end of The Avengers movie and also in Guardians of the Galaxy.
Fox is also further ahead with X-Men Apocalypse heading to the big screen next month.
It leaves DC trailing behind to explain the Justice League's main antagonist.
A couple of suggestions that they could use to help in this matter is a live action or animation New Gods movie implemented into before the release of the Justice League movie similar to Batman Assault on Arkham was for Suicide Squad. Another suggestion is that they could do a New Gods tv show this would give the average person a more better knowledge and even excitement of what to prepare for and would do much needed help to DCCU.