So I've built a new rig. On one ssd I've got Windows 8. I've got a second ssd that I want to install Moutain Lion on. I've got the .dmg file for the install but I'm unsure of the best way to go about it. Am I right in thinking I can just boot to an external hard drive with the install file from the BIOS and install that way? Any advice? I've seen a video that says I need to change the sata mode to AHCI in the bios.... Anything else?