Here it is, well, sort of… :
IMHO, running Affinity with VirtualBox is a bit “complicated” since you also need a Microsoft licence as regards Windows 10. If you want to run a legal Windows setup, I mean (no crack etc) .
Usually, when you buy a computer with Windows you are not given the opportunity to install the system on a Virtual Machine (WMware, Parallels, VirtualBox you name it).
To make it short, just run GIMP and spare you all this hassle 