This might be a noob question already answered in another post, so bear with me.
I just got a Galaxy Nexus, and I checked it and it's running one of the Samsung factory images (jakjuwx). So I'm going to flash Takju to get Jelly Bean.
I unlocked the bootloader like this: http://m.androidcentral.com/how-unlock-galaxy-nexus-bootloader.
So know I'm going to flash the Takju image. But how do I do this? Do you have to extract the software images or anything else or is it just copying them to the phone and booting into recovery, find it there and hit apply?