The problem with a question like this is you don’t define “heaven”. My default is to assume the classic Christian understanding but even this is difficult to define because every Christian denomination has a different understanding. In my travels I’ve come to the conclusion that this idea of heaven and hell as places that separate the good and the bad, with purgatory reserved for the in betweeners is a misnomer; and in my opinion one of the downfalls of the Catholic beliefs. In many major religions the concept of heaven is more a state of being. According to some orthodox christian faiths, all people go to the same “place”. What makes it good or bad is your personal perception of god himself. If you love him, then you will be happy to be there. If you hate him, then it will feel like hell. I actually like this idea because it seems to at least follow some logic and consistency within the religion (unlike the idea that a benevolent god would punish anybody).
As far as what would we do while we were there? I’d love to know! But from what is described in the Bible at least for angels is that they spend eternity in perfect unison with god. I guess it doesn’t really matter what you are “doing” as much as how you are feeling there.
Another idea would be that we would go to an Eden like place and live in a way similar to Adam and Eve, just with more knowledge of good and evil this time.
I never did understand why the Catholic Church would lay so heavily on the idea that god would literally burn you in hell for not believing in him. Like I mentioned earlier it seems really inconsistent with their fundamental definition of a benevolent and perfectly loving god. Idk.