Noob Geezer, copied example T6603 from Github, won't compile for me?

Other Hardware Sensors
5

So I just copied & pasted from: https://github.com/thebrianmanley/T6603/blob/master/T6603.cpp

I see no setup() ????

#include "SoftwareSerial.h"
#include "T6603.h"

T6603::T6603() {

}

T6603::~T6603() {

if ( NULL != _serial ) {
delete _serial;
_serial = NULL;
}
}

void T6603::begin(uint8_t rx, uint8_t tx) {

_serial = new SoftwareSerial(rx, tx);
_serial->begin(19200);
}

int T6603::get_co2(void) {

_serial->overflow();
_serial->write(FLAG);
_serial->write(BRDCST);
_serial->write(0x02);
_serial->write(CMD_READ);
_serial->write(CO2_PPM);
delay(50);

for ( int attempts = 0; attempts < MAX_ATTEMPTS; attempts++ ) {

byte reading[5];
int bytesRead = 0;

while ( _serial->available() && bytesRead < 6) {
reading[bytesRead] = _serial->read();
bytesRead++;
delay(10);
}

if ( reading[0] == 0xFF && reading[1] == 0xFA ) {
int i = 0;
i |= reading[3] & 0xFF;
i <<= 8;
i |= reading[4] & 0xFF;
_lastReading = i;
return (_lastReading);
}
}

return (_lastReading);
}

byte T6603::get_status(void) {

_serial->overflow();
_serial->write(FLAG);
_serial->write(BRDCST);
_serial->write(0x01);
_serial->write(CMD_STATUS);
delay(50);

for ( int attempts = 0; attempts < MAX_ATTEMPTS; attempts++ ) {

byte reading[4];
int bytesRead = 0;

while ( _serial->available() && bytesRead < 4) {
reading[bytesRead] = _serial->read();
bytesRead++;
delay(10);
}

if ( reading[0] == 0xFF && reading[1] == 0xFA ) {
return ( reading[3] );
}
}

return (NULL);
}

void T6603::set_idle(bool onOff) {

byte cmd = onOff ? 0x01 : 0x02;

_serial->overflow();
_serial->write(FLAG);
_serial->write(BRDCST);
_serial->write(0x02);
_serial->write(CMD_IDLE);
_serial->write(cmd);
delay(50);

for ( int attempts = 0; attempts < MAX_ATTEMPTS; attempts++ ) {

byte reading[3];
int bytesRead = 0;

while ( _serial->available() && bytesRead < 3) {
reading[bytesRead] = _serial->read();
bytesRead++;
delay(10);
}

if ( reading[0] == 0xFF && reading[1] == 0xFA ) {
return;
}
}

}

Errors:

core.a(main.cpp.o): In function main': /Users/jamespatrick/Downloads/Arduino.app/Contents/Resources/Java/hardware/arduino/avr/cores/arduino/main.cpp:30: undefined reference to setup'
/Users/jamespatrick/Downloads/Arduino.app/Contents/Resources/Java/hardware/arduino/avr/cores/arduino/main.cpp:33: undefined reference to `loop'