salam
i know i am not knowledgable enough to answer this
i will tell u what I heard from our Shayk & which we have been doing for years now
salat al Tarawee7 is a sunnah from the prophet
I remember from Abu Bakr that prophet said, in some words, that u can pray it once a day, or once a week or at least once a year
we pray taraweeh ususally in ramadan, especially kyam al layl fi laylat al qadr
i apologize if any is not exact
though I will ask about it for verification