Hello Ijeoma,
Here are the steps to set the height of the featured slider, follow the path (Customizing => Featured Section Options => Feature Slider Selection => Feature Slider Image Display Options ) :-
A) Full Screen Background
=> If you choose this option then we need to provide you css to control the height of the slider.
B) Responsive Image
=> Please add the slider’s images according to your required slider height. Because in this option, Featured slider height depends on the slider image height.
Note: If you slect option A ( Full Screen Background ) then, please inform us we will provide you custom css.