Deleting from the Grid
To delete from the grid pull up the group of sites that you want to delete from by selecting them or searching for them. Then you can click the check marks next to the specific site and press the trash can icon. You can delete more than one site at a time this way.
Deleting from the Site
To delete from the site itself you can click on the site and then open the site menu showed here. In the upper right hand corner you will find the edit button.
Once you have selected the edit button there will be a delete option in the bottom right-hand corner of the editing page. Clicking this button and confirming will delete this site.