Could you provide me full step by step solution with answers and method $($Not just method but actual calculations as well$)?$

$(16)3.$ Use Castigliano's theorem $($the least work theorem$)$ to analyze the structure shown. Calculate the maximum bending moment and shear in the beam; plot shear and bending moment diagrams for the beam. The beam has $EI=1\mathrm{.}44{10}^{4}kN*m^2$ and is inextensible. The steel rod has $EA=1\mathrm{.}25{10}^{4}kN.$