Installing windows 8.1 onto new msata

Hi, I recently purchased a precision m3800. It came with both windows 7 and 8.1 pro 64 bit. It is currently running win 7 off the 500gig hdd.
What I plan on doing is, adding the 480gig crucial m500 msata onto the laptop and installing windows 8.1 pro on it. The laptop came with one of the usb things with windows 8.1 image on it.

I then plan on replacing the 500gig hdd with a 1tb sshd.

I was wondering how I should proceed to get this job done.

I also had another question, the laptop came with a single 8gig stick of ram, I bought another 8 gig stick off amazon and was wondering if all I needed to do was plug it in.

I was also wondering, would I be able to keep a backup of the windows 7 pro to use later on in the future if ever I want to change back to that?

Thanks

Here are some details to the things I bought

Dell m3800 owners manual
http://binar.pl/p/precision-m3800/precision-m3800_owner_manual.pdf

Crucial m500 msata
http://www.amazon.ca/Crucial-480GB-mSATA-Internal-CT480M500SSD3/dp/B00BQ8RHMO

Corsair 8gb ram
http://www.amazon.ca/Crucial-Single...=204-pin+SODIMM,+DDR3+PC3-12800+memory+module

Seagate 1tb sshd
http://www.amazon.ca/Laptop-SSHD-Hy...d=1397483746&sr=8-2&keywords=Seagate+1tb+sshd

 

Yes, you should be able to just add the RAM.

For the backup of Win 7, you could image the drive, or just stick it on a shelf as is.

I would pull the current drive and add the mSATA and install windows on that, then later add the SSHD.