How do I use 3 pin fan to 4 pin pass through cable?

[bingaloman]

I'm planning on adding extra case fans to my PC but my motherboard doesn't have enough slots to carry anymore so I was told I need these 3 pin to 4 pin pass through cables. But the thing is, I'm confused on how I would plug these in?

How would I plug it into my psu and then from there to my fan?

This is the cable btw
http://www.amazon.com/gp/product/B00007FGUD/ref=oh_details_o00_s00_i00

 

[proton007]

It doesn't go into your psu.
The psu's power cables have 4 pin connectors. Connect it to one of those.

 

[bingaloman]

Oh alright thanks!