To do this search help--> answer wizard --> 'make a collapsible list'

To not have the numbers show in the browser, put insertion point at every item: Format --> Bullets and numbering -->  Numbers tab --> Style --> Format --> Numbering --> Numbers tab --> Plain box

To have the numbers not show here either, put insertion point at every item: Right click --> List item properties --> Style --> as above

1. Main4
   1. Second4
      1. Body
2. Main4
   1. Second
3. Main4
   1. Second4
      1. Body

   The above was copied and pasted to the table with two columns