I would like to use the CASTEB module in Material Studio 2024 to study the adsorption of an organic compound onto a pure metal surface(Cu(111)). I have read the steps in the Material Studio tutorial, but I don't know what to do in the step of building and optimizing the organic compound because it is too large for the given compound (as an example). Note: I am drawing the compounds using GaussView. Can anyone please help me with how to do that step by step?

 And what properties and parameters need to be changed from the default?