Templates can be removed within OpenGround (rather than Template Studio). If they include useful material which might help future design consider marking them as 'Inactive' - this will retain them on the system but prevent them being available for general use. Deleting a template will completely remove it from the system, as may be appropriate for a template created in error for example.
Templates are generally stored in a configuration pack although can be stored at project level. The steps below outline the process for a configuration pack (for a project based template open the the project and follow the appropriate buttons under the "Configuration" ribbon):
1. Open OpenGround and login as the administrator
2. Go to System>Configuration Packs
3. Select your pack (If you haven't created a new pack the pack to select will be "Default")
4. From the ribbon go to "Manage Components"
5. From the picklist select "Borehole log templates"
6. This should then display a list of all the templates that are saved to the configuration pack. You can individually delete them or mark them as inactive.