Here are my tips on taking it apart.
1. Take it apart inside at the kithen table this way if you drop a part it may be easier to find.
2. Take it apart inside an old cake pan this will catch small loose parts.
3. Keep a strong magnet handy to hold small parts.
4. During disasembly and reassembly keep the schmatic that you posted handy it can be a big help if the mystery part wont come out.