To export a 3D model from a modeling program to Unity: 1) In the modeling program, navigate to the "File" menu and select "Export". 2) Choose to export the file as an ".FBX" file type. 3) Save the exported FBX file to a folder. 4) In Unity, import the FBX file by navigating to "Assets > Import New Asset" and selecting the saved FBX file. The model is now ready to use in Unity.