Indoor Obstacle avoidance using fuzzy logic and proportional integral derivative (PID) algorithm

We are newbies on building drones and we have this research or project that we have to study algorithms for obstacle avoidance on quadcopters.

we built the drone with these materials:
-pixhawk 2.4.8
-920kv motor
-330 frame
-30a esc
-4s 2200mah battery

the problem is we don’t know where to start so we can apply the algorithms.
the goal is we need to control the quadcopter with the RC while applying the obstacle avoidance algorithms indoors then we proceed to the research.

You have to modify the code, build it and upload to the fcu. Maybe you can use Simulink PX4 Package if you already have Simulink model. In that case the controller is PX4, not Ardupilot.