To start learning Pendulum - Slam chords, build your understanding on these basic chords - Ebm, Gbm, Eb, Gb, Gbm, Eb and Ebm in sequence. I suggest starting at a calm pace of 43 BPM, and as you gain confidence, approach the song's BPM of 87. Adjust the capo based on your vocal range and chord preference, keeping the song's key of Eb Major in mind.