How To Play Slash Chords (IU's songs as examples)

How to play this 12 slash chord below. C/E, F/A, Bb/D, Eb/G, Ab/C, Db/F, Gb/Bb (F#/A#), B/D#, E/G#, A/C#, D/F#, G/B I described Paul Kim and IU's songs as examples. If you watch this video and practice it, Your voicing skills will be upgraded!^^