You can set the visibility for the enum.
You can set the visibility of the attribute based on enums, booleans or expressions on the page in the property of the input widget.
See reference document here.
You should also consider taking the rapid developer learning path as such concepts would be covered and you would be more comfortable working with Mendix.
You can apply conditional visibility on second enum based on value chosen for first enum, you have to use conditional visibility based on attribute value and select you enum and it’s corresponding values to show the second enum.
Hope it helps