This week marks the debut of Creature Commandos, a series that currently seems like a quasi-sequel to The Suicide Squad and Peacemaker. It has been revealed some elements from both projects will carry over, but not everything will make the transition. This could lead to confusion in Joe Audience (read: the general audience member), who doesn't know how all the pieces will fit together. To counter this confusion, Gunn could repeat what he did with Guardians of the Galaxy and The Suicice Squad: introducing their respective worlds through the context of it's protagonists' stories.
Within the next year, three James Gunn-created projects will see the light of day. The first official project within the DCU will be the animated Creature Commandos show. As such, it has the task to establish the new universe. It will then followed by Superman, arguably the more important project, as it is a movie starring one of the most popular superheroes of all time. Finally, Peacemaker will follow suit, who's first season -except for the Justice League scene- is confirmed to be canon. Thus, these projects will provide the context through which the wider DC universe is going to be introduced.
Introduction through context
Before taking over DC Studios, Gunn had already played in the DC sandbox with The Suicide Squad. The opening sequence follows Savant from Belle Reve to his death. Through Savant, Joe Audience is introduced to Task Force X, that it has been operating for some time, what their goal is, who it employs and who runs it. Most importantly, this sequence shows that multiple superpowered people already exist in this world. So, through the point-of-view character, where everything is introduced in context of their perspective, Joe Audience quickly learns about the what, the who, and the why of this world.
The Suicide Squad is not alone in employing this technique. Star Wars: A New Hope starts with C-3PO and R2-D2 and follows them from the Tantive IV down to Tatooine where they meet Luke. The Last of Us starts with Sarah and keeps the focus on her during the first moments of the outbreak. The Hobbit starts with Bilbo in the Shire, until Gandalf is introduced who in turns leads the Dwarves to enter Bilbo's life and perspective. Gunn's own Guardians of the Galaxy even does it, as it starts with Star-Lord on Earth, then Morag and eventually Xandar, where he meets the other future Guardians and villains.
This also works when the story unfolds in sequential order, thus never giving away information earlier to Joe Audience than to the main characters. When it does, it is relevant to, logically follows from, or is interlaced with an in-narrative story, similar to A- and B-plots in tv shows. In case of The Suicide Squad, A New Hope, and The Last of Us, it starts with another character, but through their POV the real main character is introduced. However, there is room for hints that inform of larger worlds or additional POVs, like Fury in Iron Man 1 & 2, as long as it doesn't distract from the hero's journey.
Introduction to the DCU
What The Suicide Squad shows is that Joe Audience can quickly be introduced to the moving elements, once they become relevant, of an already developed universe. Superman could follow a similar path, With multiple superheroes confirmed to appear, the film could introduce them gradually through Superman’s perspective, allowing Joe Audience to encounter these characters only when the context has been provided for their appearance and they become relevant to Superman's story, or Superman part of theirs. This keeps the focus on Superman while simultaneously expanding the DCU.
One complication with the DCU is that it's not a full reset, so new projects must establish what has carried over. One solution is to acknowledge that the universe has changed. For example, Peacemaker might be the only character aware that something -like a different Justice League showing up at the end of season 1- has changed. Without explaining how, context is provided for Joe Audience to understand a change has happened. For now, it is to be assumed that only what is mentioned carries over, including some castings like Waller -even though Frank Grillo has hinted her role will eventually be filled by Rick Flag Sr.
In conclusion, Creature Commandos, Superman and Peacemaker season 2 each play a role in introducing Joe Audience to the new DCU. Through the POV of a main character, context is provided by their relations and situations -without turning it into exposition dumps. This way, Joe Audience rapidly catches on with the what, the who and the why of that world. Like Gunn did with The Suicide Squad and Peacemaker, it could then build from there. In this case, Creature Commandos and Superman set up the world, while Peacemaker again takes a deeper dive into it's inner workings.