They are where you stored them, it's as simple as that. Or, if you have a backup on a different medium (some people don't backup their data, can you imagine that?) they are there.
However, Windows respects ownership. The two common options to access them on their original location are:
1. Boot to a Linux disc or stick (free to make) and copy those files to a FAT32 formatted device (disk or USB-stick).
2. Take ownership of the Users folder (if you stored them there). https://www.google.com/search?q=windows+10+take+ownership+of+folder tells how to do that.
Last year, the cooling fan in my Toshiba Satellite L655-S5106BN laptop stopped working. I bought a replacement fan and installed it, but for some reason the computer won't work. I removed the HDD, put it in one of those data recovery cases, and connected it to my other laptop, an HP Pavilion. Both machines are running Windows 10. When I click on "This PC" on the HP, the Toshiba HDD shows with the correct "70.0 GB free of 284 GB," but when I double-click on it the "My Files" folder is empty and the "Users" folder doesn't contain any of my personal files. Can anyone tell me why this is happening? I'd greatly appreciate any help you can offer.