Complex sentence: The public had to get used to the idea of Christensen not heading a power rock trio anymore and choosing a wider musical horizon, as he would describe as follows: Many run away screaming when they hear that there are two guitarists in the band.
Split into simpler sentences: The public had to get used to the idea of Christensen not heading a power rock trio anymore, combined with him choosing a wider musical horizon. At that time, Christensen described the audience's response as follows: Many run away screaming when they hear that there are two guitarists in the band.