There are many different types of stones, and techniques for shaping them became progressively more sophisticated over time.
With instruction, it would probably take you less than an hour to learn how to make the types of simple chopping stones that human ancestors used 1 million years ago. However, it takes much more considerable time and skill to learn how to make the types of stone tools humans were using 100k years ago. You get the sense that each group of ancient humans probably had an old expert toolmaker who passed on the trade to the next generation.
It just occurred to me that this might relate to why people get near sighted with age. An old tool maker may no longer be as productive in hunting and gathering but instead masters his or her craft thus aiding the tribe.
With instruction, it would probably take you less than an hour to learn how to make the types of simple chopping stones that human ancestors used 1 million years ago. However, it takes much more considerable time and skill to learn how to make the types of stone tools humans were using 100k years ago. You get the sense that each group of ancient humans probably had an old expert toolmaker who passed on the trade to the next generation.