SATA drives usually have no pins or dip switches. Even if it's an older ATA drive where you had to set it to "Slave" vs. "Master" , it would already have been set to "slave" mode because it was intended to be used as a supplementary drive anyways. Any other settings should not be changed either.
Once you open it up, you will almost assuredly find an a plain old, internal hard drive hooked to nothing more than a power supply an on/off button and maybe some very minor circuitry. The drive itself should have two cables. The power supply cable should be easy enough to identify, leaving the data cable.
If it's the older ATA style drive, it will be a large flat ribbon cable. If that is the case, there is going to be pins or dip switches but as mentioned above, you shouldn't need to change anything. If you find a small plastic pin connector rattling freely around in there, you also found your problem.
If it's a much smaller ended, round cable it is PATA and there is nothing to change as they are pretty much plug and play.
The only challenge you will have is maybe matching the cable to your PC. Power should be easy as your PC probably has extra power cables of different size ends. However, most newer PCs are SATA and don't have anywhere to hook up the older style drives and vice versa if older.
For your data cable to the PC, the older ATA's usually have an extra connector wired in parallel to the existing cable.
The SATA drives usually plug into internal USB ports inside the PC itself. Just trace out the existing hard drives cable to find the extra port. You may need to buy another cable though as the port is probably sitting empty. For either technology, the one in the external drive will likely be too short to be useful and may not be removable.
Hope this helps. Feel free to ask more questions once you get deeper into it. I expect to see some nice photos of the whole project.
