First, unplug your saw & clamp it to a work table.  (I like to work about 40" off the ground)

View of the chain

Use a marker to mark a tooth, so you can easily tell where you started

Sharpen all of the teeth facing right

Using a dremmel with a diamond sharpening stone, gently rub forward and back against the tooth.

Using your eye, keep the same angle.  See a video

Be careful to not let the sharpening stone jump over the front of the tooth

Repeat this process for all teeth facing left