Hey @Laurin 
,
Welcome to the community! Feel free to Introduce yourself 
to the community if you want to:grinning:!
In order to assign Speckle schemas to Rhino geometry, first make sure you enabled the Speckle Toolbar(below GIF). There you’ll see a bunch of options such as (Wall, Floor, Column, Beam etc.) Most of these options expect a special type of input. Floors expect a Surface in order to generate a native Revit floor. Or columns expect a Line in order to generate a native Revit column. You got the point.
If you want to convert your solids into Revit elements, then you can use Direct shape. Let’s say you want to receive the above extrusion under the Floor category, then you can use DirectShape command and assign the Floor category to it. Options are quite limited atm. We’re working on expanding this functionality (hopefully it’ll be ready in the coming months).
