In general the data migration process is pretty much a cut & tried procedure, but we need a bit more info from you.
1. Are you working with a desktop PC or a laptop? If a laptop, presumably you can internally install only one drive in the machine unless you have multiple drive bays or one of those caddies installed in the optical drive compartment. Which is it?
2. What's the size of your source disk and what are the total data contents on the disk.
3. Does your source disk, i.e., your boot drive boot & function without any problems.
Respond if you will and we can go on from here.