Hey Younes,
You can start by going through the Simscape Onramp in MATLAB Academy to familiarise yourself with Simscape:
Futher, you can consider the Power Systems and Power Electronics Simulation Onramp to deal with setting up Solar generation, conversions and powering the system:
Post that you can reference the various renrewable energy example models available in the documentation:
Finally, if you are looking for a refernce for the exact project you are doing, I came across the following IEEE paper:
S. Pant and R. P. Saini, "Solar Water Pumping System Modelling and Analysis using MATLAB/Simulink," 2020 IEEE Students Conference on Engineering & Systems (SCES), Prayagraj, India, 2020, pp. 1-6, doi: 10.1109/SCES50439.2020.9236716.
