Okay so first when you get to the subway, buy your ticket from the machine and that costs $5HK. Go to platform one and wait for the train. Once the train moves, you'll pass by the Jordan Station, the Yau Ma Tei station then after that is the Mong Kok station.
Once you're in the Mongkok station, go out of the D3 exit. Walk for about 2 blocks then turn left and there you'll find the Ladies Market. Thats basically it. If you have a hard time looking for the ladies market, refer to the pictures I posted from when I went to Mong Kok. That should be easier.