Have a look here: Old thread In particular lotvics advice with which I concur. I would partition the main drive into, say, 100 gig for system and programme files and the balance for your data. Then use ATI to make full images of the System partition partition and use a mirror copy with Freefilesynch or Synch toy of your data, after a scan for viruses and malware, and a defrag. Too big for a full tutorial but come back with specific questions.
Hands-on: Samsung Galaxy S8 review