Imagine an N by M array of little graphs on your figure. Those are the rows and columns. The third arg is the number of the plot starting at 1 in the upper left, going across the top row to M, then down a row and across again, then so on down row by row until the last plot, the (N*M)th, is at the lower right. For example for a 3 by 4 array of plots you'd do
subplot(3, 4, plotNumber);
Where plotNumber follows this pattern:
1 2 3 4
5 6 7 8
9 10 11 12
Use the number above to plot into the plot at that location. For example
subplot(3,4,5);
plot(rand(15,1));
will plot into the middle row at the far left.
You can also combine numbers. for example you could plot all the way across the top row with subplot(3, 4, 1:4) and then have 8 tiny plots underneath it when you use the numbers 5 - 12 one at a time: subplot(3, 4, 5), subplot(3, 4, 6) etc.
