You can learn about admin commands here: http://ark.wiki.gg/Console_Commands

Here's what you need to do:

1. Set an admin password on the "advanced" tab of your server settings in our web-based control panel. Then restart the server from the control panel so your password change takes effect.
2. Go into the game, hit TAB, and type enablecheats YourPassword
3. You can then type admin commands, such as admincheat DestroyWildDinos