1.) Download an ISO file
Before you can create a bootable disk, you need a disk image. A disk image is an ISO file containing the installation files. A simplistic definition of an ISO is a soft version of the install CD’s or DVD’s (which would be the hard version). You can a Windows 10 ISO image here. For Ububtu 16 LTS or Ubuntu 17, you can get an ISO image here. For any other ISO images, if you cautiously and carefully peruse torrent sites for well rated and verifiable ISO files, you are bound to find them (except macOS. macOS ISO’s are notoriously hard to find).
2.) Burn the ISO to a USB
Once you download the ISO file, you will need to burn it to your USB. This requires a purposefully designed burning software. If you are using a mac, your OS comes with a program called Disk Utility, for everyone else, you will need to install an image burning program like Ethcher, Free ISO Burner, or Nero Burning. Once installed, you will need to plug in a USB drive with enough available space, and then use the program of your choice to burn an image of the ISO to the thumb drive. Each program is different so you need to figure out the layout for specific instructions on how to proceed with each program. I recommend Ethcher for novices and beginners (even those using Macs) because it’s simply laid out and requires only 3 steps to get the image burned.
