I can show you how i would do.
A = readtable('..');
x = A(:,1);
y1 = A(:,2);
y2 = A(:,4);
In your code y1 and y2 are the same column. If your column 2 has less data that is NAN so it can't be plotted you can just find out the difference and delete the last rows in x and y2.
s1 = size(A,1)
s2 = size(A,2)
s4 = size(A,4)
Now you can just choose the rows you need.
x = x(2:s1-(s1-s2),1);
y2 = y2(2:s4-(s4-s2),1);
Now you have all 3 columns in your Workspace and they all have the same length. I usually convert these tables to arrays with table2array and str2double, so i could use plot(), but i'm sure there a better options like stackedplot or something.
If you converted them to doubles you can plot them in the same plot like this. If you stay with your tables, i don't know how to properly plot them.
I hope this helped you. Can't compile right now hope i didn't make a mistake.