Double click anywhere on a graph (except the axis) and the Format Graph dialog will appear. Or click the Format Graph button.
Click “Apply” to see the effect of changes
The Format Graph dialog gives you a huge number of options to change the appearance of your graph. Click “Apply” to see the effect of the changes you made without closing the dialog. This saves you time over clicking OK to see the changes, then bringing back the dialog to make more changes. Once you click Apply, the changes are made even if you then cancel the dialog. To reverse those changes, use the Edit..Undo command.