USB is not booting to install High Sierra

Hi,

I have followed a few tutorials on youtube to get High Sierra on a USB to install on my machine (this is current one I'm trying to figure out: https://youtu.be/FqyVTI-62uI, but I also tried this one: https://youtu.be/hY-rBHY8NOg) and TransMac says it's succeeding in extracting the OS to the USB. But when I restart and select to boot from that USB, it always go straight to Windows.

Can anyone help me with this?

My machine specs are:

• Intel Core i5 4690
• ASRock H97M Anniversary
• 16.0GB Dual-Channel DDR3 @ 799MHz

Thank you!