I will describe the actions that must be performed to make a bootable USB flash drive with CentOS:
1) Download the image of CentOS (namely LiveCD, looking for it usually under the buttons in “via Torrent”) from the official site
Old versions can be downloaded for example here (in isos folders) http://vault.centos.org
2) Download installer
3) We 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 “CentOS“,
“Step 2” click “Browse” and point to the downloaded iso-image CentOS.
“Step 3:” select the letter of the flash drive, tick the “Format” (this will re-partition the file system table and erase all the data on the USB flash drive).
4) Click “Create” and we are waiting for the completion of the process.