To remove the chapter starter templates from the Site Template Gallery, perform the following steps.
BE SURE TO verify that you have sufficient rights to delete a site template from the top-level Site Template Gallery.
OPEN the top-level SharePoint site where you previously uploaded the site template STP files. If prompted, type your user name and password, and then click OK.
Click Site Action, and then click Site Settings to display the Site Settings page.
Under Galleries, click Site templates to display the Site Template Gallery page.
If you see a Go To Top-level Site Settings link under Site Collection Administration, you are not on the top-level site administration page. A site template can only be uploaded to the Site Template Gallery on a top-level site. Click Go To Top-level Site Settings, and then repeat the previous step.
Click the Edit icon to display the details for the site template.
Click Delete item to remove the site template. You will be prompted to confirm your request. Click OK to complete the deletion and redisplay the Site Template Gallery.
Repeat the edit-and-delete steps to remove each site template that you no longer want available for the creation of practice sites.
3.135.202.203