I have a Late 2011 2.4ghz MBP running the latest version of Yosemite and I am going to upgrade from 4GB to 16GB and I going to ditch my 500GB HDD for a Samsung 850 Pro 512GB. I am not too incredibly technically inclined, but I familiar enough that I am confident I can physically install both upgrades. My question has more to do with how I go about booting up and installing yosemite onto the new SSD. Ideally, I just want to start fresh and not clone the contents of my current hard drive to the SSD. I am unsure if once I have the SSD installed, I can then boot up using a USB thumb drive that contains the OS X Install app or if I need to put Yosemite onto the SSD prior to installing it. Also, I'm unfamiliar with TRIM, again, I've done my best to read up on it and understand it, but do I to install TE prior to installing the SSD? What about disabling kext signing before going through the entire process? I just don't wan't to install everything and then be stuck on the grey screen. Again, sorry for my inexperience, any insight would be greatly appreciated.