The Texture Galleries let you quickly preview all the textures in the Templar Creations texture sets. Select a gallery from the left-hand sidebar. Each gallery will display a set of thumbnail pictures of the textures. Simply hover your mouse over any of the thumbnails to see the full-size view of the texture
If you want to purchase a set, or simply find out more about it, click any of the thumbnails, and you will be taken to the Second Life Marketplace page for that texture set.