This should be in the help for subplot. You want to create a 1x3 array of subplots.
subplot(1,3,1)
plot(rand(5),'.')
subplot(1,3,2)
plot(rand(5),'.')
subplot(1,3,3)
plot(rand(5),'.')
Of course, you could use a loop too, but the above is the simplest form.