Top Sites

I have been unable to figure out how to add and pin websites in my top site on my safari start page. Five of the websites carried over from before the update, and they're completely fine and don't change, but the last five randomly change as I use safari, and I have been unable to figure out how to specify what websites I want on my start page, and pin the ones I want to keep. As it is now I keep having to delete pages that show up in the last two spots because it will be websites I have visited only a couple of times and which I really don't need in my top pages, while the ones I do need disappear the next time I return to the start page. It's a really frustrating problem, does anyone have a potential solution?