This is not specified, it depends on your turntable, (if it has a pre-amp or not) and its connections. Here, to use these speakers, you will need to connect to AUX (jack). Maybe an adapter like this one could work: Value Stereo plug - 2x cinch (5 m, Entry level, 3.5 mm jack (AUX), RCA) if your turntable already has a pre-amp. :) If not, you will need to get one as well (pre-amp/DAC). LD Systems PPA 2 (Entry level)

Normally this should not be a problem, it depends on the amplifier model, but usually every amplifier has one or more line out outputs. The S2000MKIII has two line in connections. So that should work. Alternatively, you can also use the optical out of an amplifier or digital out, these connections are also available on the S2000MKIII.

No, you need speakers that can be connected via speaker cable. like this: Klipsch R-51M (1 pair)

These are active loudspeakers. Thank you very much for pointing this out. A correction request has just been sent.