Throwdowns offers a "Duplicate" feature to let you easily use one of your existing competitions to make a new competition.
To do so:
Login to your organizer account
Select "Duplicate" for the competition you'd like to copy (circled in red in the example above)
Select "Yes!" in the popup asking if you're sure you'd like to duplicate this competition
Fill out the resulting form, making changes as needed for the competition name and other fields, and then click "Save"
Work through the remaining steps to setup the programming and other portions of your competition before requesting that it be launched.
Note: Duplicated comps do not copy over your leaderboards or your registrants.
For more information on creating a competition, please see "Create a competition".