What do atheists believe?
I've seen this question asked many times, so I'll try to help.
First, the only thing that all atheists have in common, is that they don't believe in the existence of any gods. After that, each atheist can have different views.
Some atheists believe that there is no god. Most atheists don't have this belief, but simply lack belief that there is a god.
Atheism isn't a religion. We don't gather in groups to chant songs, there are no dogmas that we are required to believe, no funny headgear, no special costumes - none of the trappings that we associate with religion
Most atheists accept that evolution is true; there might be a few that don't, but I haven't met any. And that the world is a globe. And the germ theory of disease. Most atheists accept abiogenesis, but there are a few that prefer panspermia. Most atheists are willing to say that they don't know how the universe came about; perhaps it was always there, or perhaps it came from nothing (that's a whole other argument) - we don't currently know, but research is continuing.
Most atheists object to being told that we have to follow someone else's religious principles. For example, if your religion says that you can't eat ice cream on Tuesdays, then we are fine with you following that rule, but not with you telling us that we must also. So, we eat pork, we draw Mohammed Pbuh, we make jokes about the crucifixion, we don't go to worship on Fridays, Saturdays or Sundays, we think that gay people shouldn't be discriminated against, we think that women should have justice and control over their own bodies ... and so on. But there are possibly some atheists that would disagree with some of that.
Atheists also object to their children being indoctrinated by the government into a religion. Atheists tend to believe that government should keep its nose out of religion. Although some atheists might believe in the abolition of all religion.
Atheists are generally more moral than theists - we don't believe that we have a right to beat our wives, we don't think that slavery is OK, we don't think we should stone disobedient children. But we're OK with eating shrimp, wearing clothes of mixed wool and linen, and planting mixed seeds. Because we don't think that eating shrimp harms other people.
Atheism doesn't come with a specified morality, but most atheists tend to follow the idea of "least harm". So, atheists believe that murder is bad (even for religious purposes). Homosexuality isn't bad as long as it's between consenting adults. Pedophilia is bad because the child isn't old enough to consent. One useful rule of thumb is "How would you feel if someone did that to you or someone you love?" Another useful rule of thumb is "What would happen if everyone did that?" So, by those rules, you would not punch someone in the face, and you would not leave rubbish behind after a picnic.
So I hope that this helps theists to a better understanding of atheism.