Simplify the following text for a Grade 10 native English-speaking person.
Original: When guitarist Jonny Buckland started playing it and supplemented it with his ideas , they had created the riff , `` and it sort of got a bit heavier '' .
Simplified: When Jonny Buckland , the band 's guitarist , started playing it and added to it with his own ideas , they had created the riff , `` and it sort of got a bit heavier '' .