Disclaimer - not an HR specialist so I don't know if there are laws regulating PTO. I'm guessing not because I've seen it applied differently.

All the jobs I've had came with a probation period and the time off began accumulating during that time. My current job I could start taking that time off as soon as I finished the probation period. Other places you had to wait a year.

I believe that PTO and sick leave are different piles of money because every place I've stopped working at paid me for my vacation time that I had accumulated but not sick time.