I am even more astounded by your response after what I've just said. Maybe it is such a glaringly obvious question you have failed to see it.
I am saying NO CONCEPT OF GOD OR AN AFTERLIFE. So if you try to imagine you have no concept of "god" or "afterlife" and you turn around and say, "But I do." you're hardly putting in much effort.
To make another attempt think of it like this. Imagine you are a creature that comes to Earth. You have houses like humans and rooms like humans, but you have no tables or chairs. If you were to enter a human room and see these objects you would not think "Oh! They must be tables and chairs!" You would perhaps regard the objects as decorative, used for exercise, to stand on whilst speaking, etc.,.
In this respect if you view prehistoric and ancient artifacts, written works etc., then deregarded the concept of "afterlife" and "god", you may view these historical items differently than how you usually would.
As a further example, I may watch people walk into a building and see them sing together about some story. I may see them place their hands together in front on themselves and closed their eyes. If ("IF" being the key word in the entirety of what I am asking from you) these people had ZERO concept of "god" or an "after life", then what would they be doing this for?
Can you see now why the response of,"but they do have a concept of "god" and an "after life"" just doesn't hold fast to what I am asking?
We could say that they are trying to communicate silently, or that their sorting their emotions and/or memories, that they listen to a familiar story over and over because the familiar is comforting and that this place is where they go to relax, like some kind of end -of-the-day mental wind-down building. Maybe they sing together to gain a sense of unity.
In more abstract form we could even propose they go here to sit quietly and focus on the days events and prepare for sleep and plan for the next day.
THey may bury dead people for other reasons. Maybe they do so as a means to create a physical map of an abstract thought that in this case would have nothing to do with any concept of an after life (because they don't possess that concept as far as we are concerned for this exercise.) Are these dead bodies buried as if to bury memories. The use of the physical to represent an abstract experience (an emotional/learning mechanism.)
There are many different possibilities here and I can only come up with what I can come up with. I was hoping others here could offer a slightly different perspective that has evaded me.
Understand? If so go for broke. See what your imagination can dredge up and share if you so please.
Thanks