transferrring stuff

Hi fellow Mac users-I have a question for you, which might have been answered elsewhere. I'm kinda new to the whole transferring your backed up stuff to a new computer, but I do have a backup in the form of a Time Capsule/Time Machine 2TB used regularly. I will be getting a Mac Pro 5,1 sooner, and I'm wondering how to go about transferring my stuff to the new machine. I have two hard drives in my current 3,1 and I will be updating the new one to Yosemite, so it just a matter of shutting down, opening up the side, putting the older hard drives into the hard drive sleds, sliding them in so that they go in all the way, then putting the side back on and rebooting. Do I need to bother with Migration assistant?

thanks

John B