Complex sentence: At a certain time the three of them "had three different bridges and (they) spent a lot of time trying to find out which one was the best", then Jeff Bhasker collaborated to help with the track composition.
Split into simpler sentences: At a certain time, the three of them "had three different bridges and (they) spent a lot of time trying to find out which one was the best". Following this, Jeff Bhasker collaborated to help with the track composition.