You can choose a set of templates saved in your sandbox space by using an appropriate sandbox prefix. For example, if you want to preview a version of টেমপ্লেট:Test that you have saved as "ব্যবহারকারী:Foo/খেলাঘর/টেমপ্লেট:Test", use "ব্যবহারকারী:Foo/খেলাঘর" as the prefix.