It can be useful to see the buttons right beside the graph. To do this
click Customize at the top of the window and then Split Screen. Now the
left side of the window shows the buttons like a calculator, the right
side shows the graph.
two parts of the split screen need not be the same size. Put the mouse
over the split line and drag the split to the left or right.
you might want the graph to be even bigger, click Customize and then Restore
Full Screen. Now your screen is either just the calculator buttons or
just the graph. If you have just the graph and you want the buttons, click
the green button Back to the Calculator. If you have the buttons and you
want the graph, click on draw/cal.