You must choose a RWY with a long tap, on the new window you select "NAV1 (ILS approch), then a new window "ILS settings" on which you choose your "Threshold crossing height" and "Glide slope angle" settings.
(You will have an important WARNING --> "This is not an application for IFR flying" ........)
The Glide slope indicator is OK on "Big compass", "Terrain" and "Small compass" screens.