Bitten by a tree, ’shah and ’ish reorient their relationship and cling to one another—leaving their parental home (see Gen. 2:24). A separation took place as g()d slammed the door behind them.
Presumably ’adam tilled their new world well enough to sustain them. A birth took place and was claimed by Eve*. There is no mention made of any continued conversation with G*D.
Time passed. Dividing the labor, the boys, Cain and Abel, each had established their part with their care of the land and care of the animals.
The myth of the Wild West (not to be introjected directionally into this story as it would put us nearer a closed-down Eden) is the iconic struggle between the farmer (Cain) and herdsman (Abel). How is dominion going to look given such a battle royal?
From an unknown quarter (did a passing serpent suggest such an action?), Cain brought a grain offering to G*D. Seemingly simultaneously (like all experimental jumps claimed by two or more inventors) there is a competition set up as to whose product is better. Does tilling or animal husbandry have more prestige and honor?
Who better to have as a third-party judge than the very Creator with power to have exiled ’adam and Eve*. This one truly has no favorites so a win here will mean something that can be taken to the bank.
Of course, a question needs to be asked about how G*D came to be present. Was G*D seen lurking in the underbrush spying on how things were going? Was an invitation sent to G*D via the cherubim? Did an inherent sense of g()d still live in Exile through stories told around a fire by ’adam and Eve* and was it strong enough to manifest?
At any rate, the story of an elder child being discounted in favor of a younger begins beyond Eden. [It would be worth a look at Eve* (a second ’adam) supplanting ’adam before younger sons followed Eve*’s lead and took over from older sons.]
As you consider the mystery of why Cain and Abel came up with their same activity of sacrifice, the presence of G*D to play the role of judge, and the fairness or unfairness of the result, imagine at least 3 plot lines of where the story will lead.