Скачать или смотреть How to Boot From External USB Drive

Without disturbing the main operating system on the internal drive of your computer, you can boot a different operating system from an external drive via USB.

The external drive must already have an operating system installed on it.

You might use a bare drive by connecting a USB adapter to it, or you could even use a USB stick (thumb drive).

The basic steps are

1. power down the computer

2. connect the USB adapter to the drive and plug the USB cable into the computer and plug in the adapter's power cord (if it has one -- some SSDs (Solid State Drive) USB adapters get their power through the USB connection itself).

3. power up the computer and press the magic key that brings up the computer's Boot Menu. If you are too slow, the computer may boot to its internal drive. If so, power it down and try again. The magic key is F10 on the Intel NUC computers and F12 on at least some Dell computers. You may need to search in your web browser for something like, "How to I get to the boot menu on XYZ computer model ABC".

4. Select the USB drive from the boot menu and press Return. If you have several choices and don't know which is correct, try each one until you get it right.

Note, many Linux distributions have "Live" USB images and instructions for downloading a live image to your computer and then "burning" it to a USB stick. The you can use the above procedure to boot to the Linux on the USB stick.