I need help with this exercise from my homework. I have no idea about how to solve it$.$ I need an step by step solving and explanation, please.

As shown below, a three$-$span beam subjected to uniform loading on $\frac{?}{\text{b}\text{a}\text{r}}(AB)\frac{*}{b}ar(AB)$ and

$\frac{?}{\text{b}\text{a}\text{r}}(CD)$ have the same $EI(E=200$Gpa,$I={50}^{**}{10}^{6}m{m}^4),$ while $\frac{?}{\text{b}\text{a}\text{r}}(BC)$ is rigid. Under

the loading, the support at $B$ also settles $60mm.$ Apply the slope$-$deflection

method to determine the moments at all supports. Then show the moment

distribution along the beam.