Insert the flash drive.
Press the power button.
At the first sign of life/computer logo there will be a key to press to enter the bios boot menu. It might be ESC, F2, F12, DEL, INS, some other function key. It depends upon your computer/motherboard. Press the right key and you should get a list of boot devices including the HDD, USB, DVD....
Select the USB and see if you get the menu the USB flash drive boots into. Kyhi's recovery drive will boot into Windows desktop. Once it all settles down at whatever menu you get, then you can hold the power key to turn off the computer and remove the flash drive to reboot normally.