Trying to use a Billboard in 3D space

Me and my team are relatively new to Cesium. We have been developing with GIS and web for many years but not in 3D. We are having difficulties getting billboards to work off the ground. They work fine at world view but we need these markers to work on 3d mesh in the world. So we need to associate them to XY and Z or Long/Lat/Alt etc. Any ideas on how this is done. Is the only way to create a 3D object and then connect a billboard to that?

Welcome to the Cesium Community!

You can set the position of billboards knowing the latitude, longitude, and altitude of it. Here are some examples that you can take a look at: