The purpose of multi content is to allow you to take an area of the screen and have movement so rather than change a whole page, you can have just the multicontent block changing (an area of a page).
The multi content element is built using blocks, so when you add the multi content widget you will have block 1, so you setup this block the same as you would a whole page, so use any of the design elements such as pictures, labels etc. When the block is complete you can then either add a new block (block 2) or duplicate block 1 and just edit it.
To use the multi content element click/drag it onto the page then double click on it.
Click/drag any other design elements onto the block such as labels, pictures etc.
The block icons are trash can (delete), copy (duplicates the block), cog (sets properties i.e. the transition fade/slide and timing for the block) and pencil (allows you to change the block name).