I need help with working code and don't know where to start

I am a college student in an electrical engineering class, for a project we are to design a custom circuit with a function, I have decided to design a kind of air filter using a particle monitor and air quality sensor, I have a general idea of how to set it up the circuit, however I have no idea i where to start coding or even if my set up is the correct way to put it together. I am using Arduino for coding everything.
The parts I'm using are as follows
-ELEGOO UNO R3 Board ATmega328P with USB Cable(Arduino-Compatible) for Arduino
-ELEGOO 3pcs Breadboard 830 Point Solderless Prototype PCB Board Kit for Arduino Proto Shield Distribution Connecting Blocks
-Ximimark 3Pcs MQ135 MQ-135 Air Quality Sensor Hazardous Gas Detection Module for Arduino
-KEYESTUDIO Pm2.5 Dust Sensor Pm2.5 Air Particle Monitor for Arduino Mega Controller R3 Nano Micro Pro Mini
-Z&T Solderless Flexible Breadboard Jumper Wires M/M (particularly difficult in the physical circuit as I don't have any M/F wires)
-MCIGICM 5mm LED Light Diodes, LED Circuit Assorted Kit (Multi-Colored - 5 Color)
Can someone please help me build a working code that will allow the sensor and monitor to work?