Complex sentence: This was Opeth's first album with Martin Lopez after answering a newspaper ad in search for a Drummer and shortly thereafter the band also brought in Martin Mendez, a friend and previous bandmate of Lopez.
Split into simpler sentences: This was Opeth's first album with Martin Lopez, who answered a newspaper ad that announced a search for a drummer. Shortly thereafter the band also brought in Martin Mendez, a friend and previous bandmate of Lopez.