You just have to trace the lines. All refr systems have the same basic circuit. Draw a baseball diamond on paper. At the top (second base) put the compressor, at first base put the condensor, at home put the expansion device and at third put the evaporator.

The low side line will be larger than the high side line.

All refr systems follow this basic flow clockwise on your drawing. The low side connection will be in the low side line somewhere between the evaporator and the compressor.

Good luck,