General soldering tutorial can be found all over Youtube. You will need some practicing as 2 pins isn't the easiest thing to solder for beginner. You will need a soldering iron as well as some solder. Flux will help a lot.
For polarity on 2 pins, generally the ground pin is the one closer to your face and the hot / signal pin is the one closer to your back. However, some IEM has this on reverse, such as QDC.