Find a controllable contact point
Rest the side of the picking hand lightly near the bridge and play a low string. Move the contact point a small distance until the note becomes shorter but still has a recognizable pitch. Too far from the bridge can choke the sound completely; too little contact may leave it unchanged. Explore this with a single note before strumming a full chord. The useful position depends on the guitar and your hand, so listen rather than copying a rigid visual measurement.
Keep the rhythm independent of the effect
Play a plain sequence of downstrokes with light muting, then release the contact while continuing the same pulse. The change should sound like an intentional shift in texture rather than a restart. Practice this transition at the boundary between two short sections. Avoid compensating for the quieter muted sound by striking much harder, which can make the rhythm tense. If you use a pick, hold it securely but without locking the wrist. If you play with fingers, experiment with a similarly light and controlled attack.
Arrange the contrast around the phrase
Try a muted verse followed by a more open chorus while keeping the chord changes identical to your verified chart. Listen to whether the vocal becomes clearer in the restrained section. You may need to strike only the lower or middle strings rather than brushing every string with the same weight. Leave enough unmuted sound at an important harmonic arrival for the chord quality to register. Palm muting is one tool for shaping sustain, not a requirement for every quiet passage. Choose it when its shorter sound strengthens the groove and the contrast feels natural when you play the complete song.