Where did stone age people come from?

Truthfully, no one knows. There is speculation and educated guess based on an understanding (limited as that is) of available evidence. However, newest finding are turning traditional theories upside down. For instance, further study of established Clovis First sites have shown that older settlements were located on some spots where it was previously believed no others had lived prior to the Clovis cultures. Newest information shows evidence that predates Clovis cultures in North and South America by as much as 8000 years.