Creating a External hard disk

I was trying to make a external hard disk out of one of the disks in my old desktop. There was lot information available in net on that. But I could not get it right and struggled for a long time. Its easy to figure out power connection etc.
But the missing part was, "how to make the disk master". Hence this post.
To make disk as master a cap needs to be put on pins as shown in the picture. But that cap may not come with the casing. I used a cap from one of my old CD drive. If you notice cap needs to be put on only 2 pins and excluding pins on both sides.