How do you add a mesh to a LOD Level in Code?

This is probably a noob question but I thought I should ask it anyway since I can't figure it out. Does anyone know how to add a mesh into a LOD:0 level in Code? I create a empty game Object and put a LODGroup Component on with just a LOD:0 level and a Culled Level. I want to put a certain mesh in the LOD:0 level but I really don't know how to do that in code.

void OnGUI () {

         if (!selectionDetected)
         {
             OnSelectionChange();
             
             selectionDetected = true;
         }
         
         if (meshes.Count > 0)
         {
             var selectedMeshesText = string.Format("{0} selected mesh{1}: {2}{3}",
                                                    meshes.Count,
                                                    meshes.Count > 1 ? "es" : "",
                                                    string.Join (", ", meshes.Take(25).Select(x => x.gameObject.name).ToArray()),
                                                    meshes.Count > 25 ? "..." : "");
             
             GUILayout.Label(selectedMeshesText, GetExpandingTextStyle(), GUILayout.ExpandWidth(true));
             
             distanceFromTerrain = EditorGUILayout.Slider ("Distance From Terrain", distanceFromTerrain, distanceMin, distanceMax);
 
             GUILayout.Label("New Building LOD Model:", new GUILayoutOption[]{});
             prefab = (GameObject)EditorGUILayout.ObjectField(prefab, typeof(GameObject), false, new GUILayoutOption[]{});
 
 
             if (GUILayout.Button(string.Format("Create Building LOD{0}", meshes.Count > 1 ? "s" : "")))
             {
                 processedMeshes = 0;
                 
                 try
                 {
                     foreach (var mesh in meshes)
                     {
                         //Bring Old Models down to Terrain
                         ConformMeshToTerrain(mesh);
                         ++processedMeshes;
 
                         //store gameObject reference
                         GameObject objToSpawn;
 
                         //Gather Selected Building's Name
                         var objName = mesh.name;
 
                         //Gather Selected Building's Position XYZ Values
                         var objPOS = mesh.transform.position;
 
                         //Gather Selected Building's Rotation XYZ Values
                         var objROT = mesh.transform.localEulerAngles;
 
                         //Gather Selected Building's Scale XYZ Values
                         var objSCAL = mesh.transform.localScale;
 
                         //spawn object
                         objToSpawn = new GameObject(objName);
 
                         //Add Components
                         group = objToSpawn.AddComponent<LODGroup>();
 
                         //Grabbing the LOD Component on New Empty Game Object
                         LODGroup objLodCmp = objToSpawn.GetComponent<LODGroup>();
 
                         //Testing to see if the New Game Object has a LODGroup Component
                         if (objLodCmp != null)
                         {
                             SerializedObject obj = new SerializedObject(objLodCmp);
 
                             //Creating a Variable that will allow me to access the data properties of the LODGroup Component
                             SerializedProperty prop2 = obj.FindProperty("m_LODs");
 
                             //Deleting the LOD:1 & LOD:2 from the Array
                             prop2.DeleteArrayElementAtIndex(1);
                             prop2.DeleteArrayElementAtIndex(0);
 
                             //This is Crticial for the above changes to take effect.  
                             obj.ApplyModifiedProperties();
                         }
 
                         //Apply Position, Rotation and Scale to new GameObject
                         objToSpawn.transform.position = new Vector3(objPOS.x,objPOS.y,objPOS.z);
                         objToSpawn.transform.localEulerAngles = new Vector3(objROT.x,objROT.y,objROT.z);
                         objToSpawn.transform.localScale = new Vector3(objSCAL.x,objSCAL.y,objSCAL.z);
 
                         if(prefab != null)
                         {
                             Debug.Log("This is working!");
                         }
 
                         //DestroyImmediate(mesh.gameObject);
                     }
                 }
                 finally
                 {
                     EditorUtility.ClearProgressBar();
                 }
             }
         }
         else
         {
             GUILayout.Label("No segments selected.", GetExpandingTextStyle(), GUILayout.ExpandWidth(true));
         }
 
         Repaint();
     }