Before Continuing If you are WiFi Make sure to download your WiFi Drivers onto the USB.
You Can download the drivers from your motherboards website.
To Find your Motherboard do windows key + r and type msinfo32, you should be able to find it under here.
Hold SHIFT and click Restart
Select Use a device and select your Flash Drive
Select Windows 10 Pro
Select I don't have a product key (If it doesn't show this don't worry)
Select Custom: Install Windows only (advanced)
Press SHIFT + F10
Type diskpart into the CMD
Type select disk # (# = for every disk number) and clean for every disk you have except your Flash Drive
Your Flash Drive is likely the last drive listed
(DO NOT DELETE IT)