Step one:
Choose a right handed coordinate system. As you can see in my schematic: 
The $X$ axis lies along the beam:

So, in $ZX$ plane, the counterclockwise moment is positive.
Step 2:
Horizontal and vertical equilibrium:
The horizontal equilibrium is evident so i skip it.
The vertical equilibrium:
$$R_E +R_C + -2 [\frac{kN}{m}]\times 2 \times \frac{1}{2}-3 [kN] = 0 $$
$R_C$ and $R_E$ are the reaction forces, i demonstrate those as they point upward but you can choose those pointing down. The third term represents the resultant of the distributed load, (the area under curve), notice its point of application.
Moment equilibrium:
I choose point $C$ as the reference.
$$1.5 [kN.m]+3[kN] \times 1[m]+2[kN] \times \frac{4}{3}[kN.m]+V_E \times 2 [m]=0$$
Now we can eventually find the value of $R_E$ and substituting it in the first equation gives us the value of $R_C$.