Complex sentence: This creation took place in the underground part of a secret research laboratory in an alternate timeline and he travels to the main timeline via a time machine stolen from Trunks, because he was unable to find No.17 and No.18 in his timeline.
Split into simpler sentences: This creation took place in the underground part of a secret research laboratory. This happened in an alternate timeline and he travels to the main timeline via a time machine stolen from Trunks, because he was unable to find No.17 and No.18 in his timeline.