Depends on the boot mode for the machine you want to boot with the USB flash drive, choose one of the following methods to setup Clonezilla Live on your USB flash drive using GNU/Linux:
How to make Clonezilla USB bootable flash drive from Windows. Clonezilla software is a free partition or disk clone tool that works similar to Norton Ghost and Partition Image.
To begin, you'll need to create a Clonezilla bootable USB drive. This article from EaseUS includes a step-by-step guide to create Clonezilla USB with Rufus. It also introduces an alternative and most effective tool to create bootable Clonezilla USB ef
This article shows you in detail how to create Clonezilla USB with Rufus, and shows you an easier way to create bootable USB and do disk clone by third-party software.