1. Unzip the modeler .zip file.
2. Copy the modeler folder to the Houdini 18 settings folder.  On my PC this is found in the C:\Users\mald\Documents\houdini18.0 directory.
3. Find the houdini.env file and open it in a text editor. On my PC this is also in the same directory as above.
4. Add the modeler path to the env file by typing
	MODELER_PATH = 
	
and type in the path to the directory where your modeler folder is.
On my PC this is C:\Users\mald\Documents\houdini18.0\modeler.
So the final command is
	MODELER_PATH = "C:\Users\mald\Documents\houdini18.0\modeler"
5. Also then type next line
	HOUDINI_PATH = "$HOUDINI_PATH;&;$MODELER_PATH"
6. Save the new houdini.env file as text.
7. Open Houdini and go to the shelf tabs(Create/Modify/Model etc). Click on the "+" icon at the end of the shelf and select "Shelves" from the dropdown.
8. You will see a list of available shelves and "Modeler" should be one of them. Select it and the Modeler shelf should appear.
9. Save the new desktop with the Modeler shelf.