Question: how do i download apps on my apple tv 3rd generation?
Answer: Sorry!! but you can't download apps on apple tv 3 whatsoever,you have to use whatever apps are available and is up to apple to add or remove apps,the new apple tv 4 has an app store similar to the one on iphone/ipad and it allows you to download apps,although i don't think the xfinity app is available yet.