New SSD help

[The Kraken]

I have a mid-2012 Macbook Pro 13" and the hard drive is no longer working. I have used time machine to back up everything to an external hard drive I luckily bought just before the hard drive in my mac died. My question now is what do I do? I've bought a Samsung 850 eve SSD because I decided I wanted to try out an SSD but I have no idea what order to do anything in. I know how to install the new hard drive but was't sure when to do this as many tutorials connect the new hard drive via usb to sata cable first to format/copy everything from their existing drive over to the new one but obviously I don't need to do this. Do I connect it via usb first to format it and then just install it and follow tutorials then on how to boot into that new drive or can I install the new hard drive straight away and just transfer everything from my external drive onto the SSD and it then start up as normal?
Thanks for your help

 

[The Kraken]

https://support.apple.com/kb/PH18848?locale=en_US I found this link on the apple site but it doesn't mention anything about whether I should connect the new hard drive via usb and format it before installing it in the case

 

[honestone]

I went through a "similar" experience when I replaced the slow, 5400 rpm 1 TB hard drive inside my late 2012 Mac Mini with a fast Samsung 256 gig SSD, but the hard drive was fine. But, first a basic question: how are you posting here? Are you using the 2012 MacBook Pro to do that, and if so, how are you booting that machine? Additionally, you stated that you used Time Machine to backup up "everything" before the internal drive went bad to a new external drive. A SuperDuper!backup would have been better, as it makes a bootable backup/clone of your system.

You will need to erase, format, and partition the new SSD first, then install the Mac OS you are using (if it is Yosemite, that will get you to OS 10.10, but you will need to take 3 additional steps to get to OS 10.10.3 and the latest version of Safari). You would then use Migration Assistant to migrate all the non-system files, folders, etc. from that Time Machine backup to the SSD. Migration Assistant can not (and will not) migrate the OS and related system files. Hence, that is why you need to first install the Mac OS before using Migration Assistant.

But, first you need to let us know what "bootable" state the MacBook Pro is in.