The installation media from the techbench link above will come in the form of an ISO file (make sure you get the proper bit architecture for your system 32 or 64)
When you save the ISO file to your computer be mindful of the location you save it to.
Now depending on what you want to do and to some extent the type of machine you are dealing with (legacy versus UEFI BIOS, mbr versus gpt partition schema) you will need to configure the System Setup Utility (BIOS) to boot first to either optical media (DVD if that is what you create) or an attached USB device if that is what you create.
Normally this can be performed by simply evoking the boot menu during POST by just selecting the option from the boot menu without needing to hard set it within the BIOS.
You'll need to know how to do this as the key or key combination varies widely between computers.
You can Google it, or......
Post some specifics as to your exact computer and perhaps someone will be able to help you here.
BUT first you will need to convert the ISO you have into bootable installation media.
You can use ImgBurn to burn the ISO to a DVD
http://imgburn.com/index.php?act=download
OR
You can use Rufus to burn it to a USB ThumbDrive
http://rufus.akeo.ie/
Then you should be able to use either to boot your system.