Go to Substrate settings that are found in either Momentum or EMDS drop down from tool bar. Once there choose create or modify substrate, that opens a new window were u need to define ur substrate layer configuration. Default it will be a closed Ground plane and an Alumina Substrate.
1) change the Ground plane from closed to OPEN and other than alumina define a layer below alumina with the properties of air. (eps =1 , mu=1)
2) define ur main substrate Parameters in parameters alloted to Alumina, U can rename it if u want.
3) Find a Tab in that window named layout layers.
4) From below between ur first and second layer , i.e air and alumina, click and define it as a slot, parallelly, check which layer are u defining for slot like cond or cond2 etc..
5) define another layer between alumina and upper air layer, assign this to be a STRIP and if u have assigned cond for prev step, now change it to some other name els u wont be able to assign strip.
6) Setup ur design in Layout and the structure U make for Lower layer, assign cond to it ( or what u assigned in step 4)
7) layout ur design for upper layer and assign material to be cond2 (or what u assigned in step 5).
8) u can check ur design by generating a 3D model option found in EMDS drop down..!!
Regards.