GO to dashboard->submissions and click the submission to edit.
Click add media on top menu of the selected submission

 

 

 

 

 
 

 

 

Click Create Gallery and select multiple images you want to add on the gallery for the submission being edited.

 

A code like this format [gallery ids="923,921,920"] will appear on the last position of your cursor. You can change the position of the gallery by simply moving this code anywhere on the page being edited.

A Featured image would be displayed on the list page of the main page.
You can set the Featured image by clicking Set Featured Image on the lower right side of the edit page.

Add <!- -more- -> on the body of the page to set the ending of the excerpt. This will be translated to Continue Reading on the list page. If you want the thumbnails to appear on list page, add the gallery code above <!- -more- ->

You may check http://odesk-demo.boonplanet.com/submission/mark-elliot-zuckerberg/ or other submissions on the dashboard using the admin account to see examples of how the codes are implemented.
Please use the Text mode instead of Visual mode on the top menu of page being edited.