Since you're not used with Linux, i also can recommend you tools called GNOME Disks (sometimes called Disks).
It's easier to use and less risky, see this guide, https://www.techrepublic.com/article/how-to-create-disk-images-using-gnome-disk/

On a side note, i hear gaming on Linux is better thanks to Proton (see https://en.wikipedia.org/wiki/Proton_(software) and https://www.protondb.com/)