Are you asking about retro-fitting bi-xenon into your halogen housings? There isn't really a DIY on it (that i know of), but you can look up some stuff on www.hidplanet.com forums for help.
www.theretrofitsource.com has great stuff and good advice on doing so.



starting here, pretty obvious.
this round black disc holds the bulb in its place. Turn counterclockwise to unscrew, then the bulb can be removed. Note the alignments of the disc as well as bulb so re-assembly doesn't take forever.
that metal connector on black disc is what's the trickiest part of reassembly. You need to keep the bulb in its place with a finger as you use the other fingers to align an twist shut. Once you feel it 'drop and snug' the ballast reconnection is easy. 