I want to mount a DVD-ROM to my PC but I can't find one jumper. Can you help me?

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So this is my problem. I want to mount/assemble/install the DVD-ROM to my PC which I bought yesterday. So I opened the case I put the DVD-ROM on I joined it to the supply and the interface cables. But my problem is that I have already a CD-ROM on my computer and in this case I installed the DVD-R with a new interface cable which I joined in the second port on the motherboard. And this is why I need to find something called "jumper" and make it "slave". Usually it is "master" but in this case I have to make it "slave" Can someone help me?