Add Custom Drone Design in SITL Simulation and how to add same parameters for drone in simulation

I am working on a drone simulation project and I need to add a custom drone design to the simulation environment. Could you guide me on how to create and integrate a custom drone model into the simulation? Additionally, I need to know how to define and configure custom parameters for the drone, such as weight, motor specifications, and flight dynamics. Any detailed steps, examples, or references would be greatly appreciated!

some clues : Customizing SITL Multicopter Simulations: Tailoring Realism to Your Drone

Thank you for sharing the documentation on adding and customizing SITL simulations. Should I encounter any issues or face any challenges, I will reach out for your guidance.

Hi, were you able to change the weight parameter for the simulations?
If you were able to please let me know how, as I am trying to simulate drone mission with varying weights.