"It goes on either way, both of the ends on the master link should have grooves in them that show through the capped end.. just slip the retainer clip back over one and slide it to clip it on the other, you can also use a screw driver to do this to make it easier… just BE CAREFUL."
ummmmm hopefully you mean that the link itself can go on either way. the retainer is very important to put on correctly.
look at the retainer carefully. you will see that one side has kinda rounded edges while the other side has sharp square edges. the square edges must face out. now, when installing the retainer, put the rounded end in the direction of chain travel and the open end to the rear. if you do not do this, eventually the retainer will come off and you will lose the master link. not good at 30 mph.