If you take a look on the back of the mini fridge there usually is a big sticker which gives a bunch of technical information about the fridge and in some cases gives some crude diagrams about where the freon line runs across the top of the fridge. If it doesn't have any detail, you can do a couple tricks, one which involves cornstarch, to use the heat given off by the lines to find them. If you plug the fridge in and turn it on, you should be able to feel the heat coming from the line.
Heat is only given off by the condenser lines. The evaporative lines are the cold side. Both sets of lines are tied together and damaging either will destroy the fridge.
I would try to google refrigerant schematics for that model, or find a refrigeration forum to ask.