According to this video the sounding of The Last Trumpet (100th) on the Feast of the Trumpets 2017 will call for the 1st Trumpet of Revelation Story of the 7 Trumpets. Moreover this will be then, also according to this video, the start of the pre-Tribulation Rapture.
This Rapture thing is very popular among Evangelistic American Christians. I don’t know why!? OK I did not do Bible study on this theme, could be true, could not be true. Anyways the 7 Seals will be opened before that time (I think). Can be that the book of Revelation is not chronological from beginning until the end, but more mixed and intertwined. The Seals will open themselves by the way, not that The Lamb causes them, it are only unstoppable world events. The Lamb merely interprets them, no more no less.