Hi.
I have asked couple times about making simple bench grinder to belt sander conversion, that doesn't require many tools.
This solution was the simpliest that i found.
https://youtu.be/oC7nirxvkFI
I also made improved version from it, pictures / video comes later.
With bigger pulley and belt tensioner.
https://youtu.be/H_OWvB7rEDM