Complex sentence: Manager Brian Epstein moulded them into a professional act, and producer George Martin guided and developed their recordings, greatly expanding their popularity in the United Kingdom after their first hit, "Love Me Do", in late 1962.
Split into simpler sentences: Manager Brian Epstein moulded them into a professional act and producer George Martin enhanced their musical potential. They gained popularity in the United Kingdom after their first hit, "Love Me Do", in late 1962.