I think i finally get it. For a given pair i would have that
$$
F_{XY}(x,y)=
\begin{cases}
0,x<0,y<0\\
0.2+0.1,0\leq x<1,0\leq y<1\\
0.2+0.1+0.3,0\leq x<1,1\leq y<2\\
0.2+0.1+0.3+0.1,1\leq x<2,1\leq y<2\\
0.2+0.1+0.3+0.1+0.2+0.1,1\leq x,2\leq y
\end{cases}
$$
or
$$
F_{XY}(x,y)=
\begin{cases}...