Simplify the following text for a Grade 9 native English-speaking person.
Original: Stefan Elmgren played some of the guitars on the Glory to the Brave album ( such as the acoustic guitars on `` I Believe '' ) and Patrik RÃ fling actually played the drums on all songs in place of Jesper , but only as a guest performers , not members of the band .
Simplified: Stefan Elmgren played some of the guitars on the Glory to the Brave album ( such as the acoustic guitars on `` I Believe '' ) and Patrik RÃ fling actually played the drums on all songs in place of Jesper . However , at the time they were considered as guest performers , not members of the band .