You start by reading the plot documentation, which tells you that if both X and Y are matrices of the same size, then "The plot function plots columns of Y versus columns of X."
We love reading the documentation, because it tell us all how to use MATLAB.
>> X = [1,2,3;2,3,4;4,5,6]'
X =
1 2 4
2 3 5
3 4 6
>> Y = [1,0,2;1,2,3;2,1,2]'
Y =
1 1 2
0 2 1
2 3 2
>> plot(X,Y)
