I will give an example of creating a bootable flash drive with VyOS.
1) Download the ISO image of VyOS from the official site vyos.io
2) Download “Universal USB Installer”.
https://www.pendrivelinux.com/universal-usb-installer-easy-as-1-2-3/
3) Connect the USB flash drive to the computer and run the Universal USB Installer. In it, we agree with the license agreement by clicking “I Agree”, in the second window where “Step 1:” choose “Try Unlisted Linux ISO”, where “Step 2” click “Browse” and point to the downloaded ISO image.
In “Step 3:” we will select the letter of the flash drive, tick the “FAT32 Format” (this will remap the file system table and erase all data on the flash drive).
4) Click “Create” and wait for the completion of the process.