You can use this, but one I found later, Ventoy, is even better.
Create a bootable ISO of Ubuntu using YUMI. Then add a bootable ISO of Slax later. Then add a bootable ISO of Windows 10 64-bit later. When you boot to the YUMI flash drive, a menu appears and you simply select which one to install.
The beauty of YUMI is that it allows you to have a dynamic flash drive you can use to install different operating systems. I say dynamic because you don't have to create it with all ofthe operating system choices at once, you can add ISOs (and even remove them) as needed.
Wonderful software.