Deciphering a wiring diagram

I'm currently faced with having to decipher this wire diagram and connect it to an ArduinoUNO; unfortunately, I am a complete electronics newbie and do not know how to set this up correctly. This is a circuit for operating a TEC (Peltier cooling module) controlled by an ArduinoUNO.

Here is the associated code:

const int therm = A0;//thermistor
const int VDD_GOOD = A1;//logic voltage check
const int VM_GOOD = A3;//motor voltage check
const int VD = 10;//digital 5V for logic level and thermistor
const int VM = 9;//Power 12V for TEC
const int TEC = 11;//TEC power mosfet
const char delimeter = ',';
const String msgTag = "m";//to write messages to tablet
const String dataTag = "s";//to write data to tablet
const String endSig = "\n";//to end a transmission to tablet
const float bound = .3;// +/- overshoot on temp
const float A = .001129148; //thermistor constants
const float B = .000234125;
const float C = .0000000876741;
const float R = 9890.0; // Resistor value used in thermistor circuit
const float Temp_Limit[] = {48.0,90.0};
const float TIMEOUT = 10000.0;// Timeout for TEC when it's trying too hard and not getting anywhere.
SoftwareSerial xSerial(3,4); //Rx, Tx
int userData[20] = {};

I've connected "Thermistor signal" to A0, "Vdd_good" to A1, and "Vm_good" to A3.
I'm wondering where "+5V from arduino here" goes to (the code says it goes to Pin #10).
I'm also confused as to where "Power positive" connects to (the code says Power 12V for TEC at Pin #9).
Finally, what is the purpose of the control signal/ground?

Apologies for being almost clueless.. if anyone could give me a hand here that'd be awesome.

If that circuit board is commercial, I suggest to try to find the documentation. If it is home made, it might not even work as intended. The comment makes clear that the thermistor is essential for proper operation, but what value?