How can i publish my content with Schedule
If you aren't concerned with the "random content" portion of your question you could use the scheduler module to accomplish the task - https://drupal.org/project/scheduler which would allow you to set specific times during the day when you wanted content to be published. 

If you do want it to be randomized though, you're going to need to use rules - https://drupal.org/project/rules and VBO - https://drupal.org/project/views_bulk_operations.

(I'm assuming Drupal 7)


Create a view.
Under Fields add a "Bulk Operations: Content" field. Set the number
of entities to your desired number (in this case 2.) Set it to
publish content, Enqueue the operation instead of executing it
directly.
Under Filter Criteria set it to  "Content: Published (No)."
Under Sort Criteria set it to "Global: Random (asc)"
Under Pager set to "Display a specified number of items" and choose
the number of desired items (in this case 2)
Save your view.
Now to go Rules configuration.
If you are only running cron once every 24 hours (at 13:00) you
could trigger this on cron run, otherwise you'll need to set up some
additional steps. Assuming the 24 hour cron, set your rule to
execute when "Cron maintenance tasks are performed".
Under actions click add action then select "Load a list of entity
objects from a VBO View." Select the view you just created from the
value dropdown. Click save.
Then under actions click add loop. Default variable name at the
 bottom should be "list_item." Click save.
Now click the add action button horizontal to the loop you just
 created. Select node publish content. For the "data selector" field
 use list_item from the loop above. Click save.
Run cron to test.


2 random pieces of content should publish.