transfering data from one hard drive to another

I got this sata cable, wondered how I could transfer the data.. Then I look into the computer and see two connectors of the same, its the other cable (dont know the name). Would it be possible to connect both hard drives with the two cables with the sata cable? to elaborate, I use those two cables and plug each in, then I plug the sata cable into both. Would that work? Or would the computer not recognize anything? TY in advance.

You only connect one SATA cable to the motherboard for each hard drive and run one SATA power cable from the PSU to each hard drive, then Windows will see 2 drives on boot up and you can copy between them. You don't plug one SATA cable between 2 HDD's.

I got ya, I can see the bigger connectors are for power reasons, while the sata cables are the actual connection. Once I opened it up and looked around, it is quite obvious how it works. It all feels complicated until I do just feel around the machine... Perhaps some day I will actually just build my own computer.:)