The most important reason anyone is an atheist

[Whateverist]

I wanted to start a conversation on philosophy but no one could tell me the meaning of this word.
The same with religion and with all other issue but no one could tell me the basic which are how the religions started, what is the difference between religion and spirituality and so on.

I can't tell you the basics of religion or spirituality. There are many different traditions of which religion or spirituality plays a part. I also can't tell you what gods are, but then even those who claim to know what they are don't agree on a description. You probably have your own idea of what god is and you're welcome to it. But since I don't have one it isn't a topic of interest to me.

I do believe in consciousness however because I have direct experience of that. My suspicion is that our brains are elastic enough to support not only the program we call our conscious mind but also others, including whatever it is people believe to be their god.

We could discuss philosophy. I have some ideas. My own philosophic bent is toward plain speech. If a thing can be said at all it should be possible to say it simply. Anything which cannot be said plainly is suspect. The chief purpose of philosophy is to sketch out what is and isn't known in areas which are not yet fully understood.

There is also a history of philosophy. Unfortunately, many seem to think philosophy is a kind of bazaar where one can look for positions and opinions one might like to hold. That may be what many people do with it but that isn't philosophy.