hello fellow simmers, A while back I heard that you can customize the 737 6/7 flight deck, I've triwed to figure it out but can seem to get it. Although I'm sure im missing something very basic, how do I go about customizing it to match various airlines setup??

If im following you corectly I assume you mean how the displays look etc rather than graphic changes (which is not allowed). Anyway, all the customisations are done through the PMDG options menu, allowing things like flight director style, call-outs, rising runway, angle of attack indictor etc. Also you will need to have the -800/900 add-on to change how the PFD/ND look. This will allow you to have the standard PFD/ND and ECIAS arrangement, or to have the older classical -300/400/500 display styles (side-by-side style).