Complex sentence: The Autobots who were not able to return to their original dimension because of the collapse of the space bridge so they attempt to artificially create a space bridge of their own with the power of the three Cybertronian ships.
Split into simpler sentences: The Autobots who were not able to return to their original dimension because of the collapse of the space bridge. They attempt to artificially create a space bridge of their own with the power of the three Cybertronian ships.