After a lot of work Genaro got his sensor to work with some help.

Below is an explanation on the parts of code that may be unfamiliar to a beginner to programming.

#include <SensirionI2CScd4x.h> Declare Sensirion Library
#include <avr/sfr_defs.h> (Ask Nick)
#include <Arduino.h> Declares basic Arduino library
# include <EEPROM.h> Because data on Arduino deletes as soon as power is cut off, and we have no memory card, we declare EEPROM library which has functions that write to and from addresses to store data. Although it’s commonly used to store small amounts of data due to the typical size of EPROM chips being between 512 bytes and 4 kilobytes with our Arduino mega 2560’s EPROM being 4 kilobytes, it will last for 5 hours.
# include <Wire.h> Declares I2C library (I don’t know why they don’t just call it I2C).
# include <math.h> Contains multiple mathematical functions for manipulating floating-point numbers.
bool PRINT_CSV = true; A bool can only be true or false with each bool occupying 1 byte of memory. We set the bool equal to true because any non-zero integer is equivalent to True (AKA 1 and high) which in this case, the PRINT_CSV will display numbers above 0 as the co2 and humidity readings will never be negative. We use bool instead of booleon because booleon is only compatible with Arduino whereas with bool, if you tried to compile it to something else like c+ or c++ (which is the code for our main code), it will work only with bool. The syntax is bool variable = value.
Int MEM_LIM = E2END (ask Nick)
Int eeprom_i = 0 (ask Nick)
SensirionI2CScd4x scd4x calls upon the library arduino-i2c-scd4x/SensirionI2CScd4x.h at master · Sensirion/arduino-i2c-scd4x · GitHub
void printReading(int co2, double humidity) continuously prints CO2 and humidity readings to the serial monitor with the humidity reading set to double meaning that the implementation is exactly the same as the float because humidity outputs only 2 values as opposed to the CO2’s 4. 
if*(PRINT_CSV)*Serial.println(string(co2)*+*”,”*+*String(int(humidity))) if the PRINT_CVS is true you can display the CO2 and humidity readings as a string data type.
else Serial.println(“\n(“ + String(eeprom_i) + “)\nCO2: \t\t” + String(co2) + “ppm\nHumidity:\t” + String(int(humidity)) + “%”)
} Else (if the PRINT_CSV is not true AKA a non-zero integer), display the co2 and humidity as a string data type showing 0.
Byte compressReadings(double co2, int humidity) We must compress data to go to EPROM. Compressing means losing data and rounding.
{double co2_clamped = max(CO2_MIN, min(CO2_MAX, co2)) – CO2_MIN declares double co2 (double being when the implementation is the same as the float) to be the min and the max. We take clamp co2 readings between the min and the max and subtract off the min to start from 0 or some arbitrary value depending on the max.
Serial.println (“CO2_MAXXXXXXXXEDDDDDD: “ + String(co2_Clamped)) displays the clamped and rounded off readings next to the actual readings during live sampling for convenience.
double co2_double = co2_clamped / ((CO2_MAX - CO2_MIN) / 16); 
rounds to the nearest 16th using basic mathematics
int co2_4bit = int(co2_double + (co2_double - int(co2_double) > 0.5))
if the decimal place is greater than 0.5, round up, otherwise round down.
int hum_4bit = int(humidity / 6.25) << 4; 
If the humidity is less than 4 (humidity only has 2 number outputs), round down, else round up.
return co2_4bit + hum_4bit;
Return the co2 in addition to humidity.
void saveReadingsToEeprom(double co2, int humidity)
Stores readings to the EPROM with their respective data types.