Fitting boost gauge sender?

[Rich00p]

this question must get asked so much, but I'm going to ask it anyway..

I was given quite a nice looking boost blue led boost gauge and sender unit before I bought my TDi, not normally something I'd be into but I've decided to try and get it going.. otherwise it will just sit in a box doing nowt

now, I'm ok with actually mounting the gauge, I just don't have a clue where or how to hook up the sender!