Complex sentence: Fifteen years later, Eobard (as Harrison) founds S.T.A.R. Labs with Caitlin Snow and Cisco Ramon as employees and makes a particle accelerator years sooner in late 2013 which explodes, killing civilians and making metahumans as well as achieving Barry's destiny 7 years earlier.
Split into simpler sentences: Fifteen years later, Eobard (as Harrison) founds S.T.A.R. Labs with Caitlin Snow and Cisco Ramon as employees. They soon make the particle accelerator in late 2013 which explodes, killing civilians and making metahumans as well as achieving Barry's destiny 7 years earlier.