How do mining software + mining pool work in a nutshell

[danialzo]

I am very curious to understand the whole process of mining a block (from pool distribution, mining software, GPU/ASIC work distribution). How does the whole process look like?

1- How does a mining pool distribute works between miners?
2- How does a mining software handle the work? Does it break down the work further and distribute between GPUs/ASIC chips?
3- How does a mining pool validate the works done by miners? and allocate shares?
4- How does a mining pool reward the miners based on shares?