Know what the shape contains
A typical power chord contains a root and a fifth, sometimes with the root doubled an octave higher. It omits the third, so the shape alone does not specify major or minor quality. That makes it useful in some textures, but it does not mean the song's harmony has no quality. A vocal, keyboard, or another guitar can supply the third. Listen to the complete arrangement and keep the underlying chord name in mind even when your own part plays fewer notes.
Control the strings you do not want
Form a comfortable root-and-fifth shape and pick only its intended strings. Use light contact from the fretting hand to quiet neighboring strings when practical. Start with single attacks and clean stops before adding a repeated rhythm. Unwanted open strings can create a different harmony or make a distorted sound difficult to control. Move the shape between two roots while keeping the pulse steady. Let the hand release excess pressure during the shift rather than sliding a fully clamped grip unless you want an audible slide.
Compare the reduced harmony with the melody
Play a section first with the full major or minor chords, then with power chords. Listen for whether the reduced sound strengthens the arrangement or removes an essential emotional distinction. A sparse verse may need the third more clearly than a dense chorus does. If the AudioChords label includes a seventh or suspension, check whether that color belongs to your part or another voice before omitting it. Power chords are a deliberate voicing choice, not a universal substitute for every symbol. Use them when their open, direct sound serves the musical role you are trying to fill.