You might have done this before. Figure out how the cable will exit the housing. Clamp the cable and the connector so they are in the correct position. Cut the outer insulation back so it will be within the housing, but the wires are all too long, so fold them right out of the way. Start soldering with the wires going to the pins nearest to the cable, don't make then too short, leave a little slack, proceed to solder up working away from the cable until you get to the far end. If your connector is laying on its side, do the top side first then turn it over and do the other side.
Frank