Red = hot. This goes either on the pickup selector (where you removed the wire for the old one) or a terminal on the volume pot (middle is out, one of the outside terminals will probably be bent onto the body of the pot, you solder to the one that isn't)
Black AND plain are ground (you need to solder both to the groundpoint, usually back of vol pot)
Green & White = for coil splitting only, should come soldered & taped together. Leave them unless you want to coil split.
+1 on metalgod's comment about scr@ping old cr@p of the iron. I asked about the wattage because you need at least 25 (I think BKP documentation even says this). Trying to get a 2-con wire off with a 12 watt (as I once attempted :lol:) is an exercise in frustration & brute force....