You can't just plug a turntable into the lepai. You need an RIAA pre-amp in between the turntable and the Lepai. Once you have one you need to screw in the ground wire and connect the signal wires from the turntable to the pre-amp, and then connect the pre-amp outs into the lepai inputs.
Here is a link to an affordable pre-amp for your turntable:
BehringerPP400, the GoGroove may be similar or the same thing.
Which model speakers?