To get “reflections” on translucent material you need to fake it with a cubemap.
Place a SceneCaptureCube at the middle of your water surface about ten UU above it.
In the content browser package of your choice right-click and find under “Materials & Textures” Cube Render Target
Assign the CRT to the SCC property “Texture Target”
By default the SCC updates every frame. You can turn this off in its properties if you want
Drag the CRT into your shader and multiply it with a Fresnel to simulate Angle Of Incidence effect. Change the AOI with the exponent value of the Fresnel. Higher number means higher AOI before the CRT is full bright.
Connect that to emissive slot
I find that leaving the normal input of the Fresnel empty works best.
To get a basic wave action you need a tessellated mesh
For waves copy my network. The wave length should be at least the distance of three vertices in world space otherwise it just looks bouncy. So if your mesh verts are 100 uu apart, make the divisor 200.
