You will need to run 2 cables per channel and a signal cable from the amplifier to the car adapter. This connection can be either butt-connected with crimp style connectors or (better) use soldered connections with heat-shrink. I recommend a piece of scotch tape wrapped around a sheet of paper to label the ends of the wires. The other option instead of scotch tape is clear heat shrink. This really leaves a really nice looking label.
To connect the source, in this case the android tablet, a stereo mini to rca (red and white) is needed. If you plan on having the device charge while it is being used, a ground loop isolator will needed to be added to this audio circuit. If powering the device and also using it as an audio source without this isolator you will hear a lot of static.