Guitar: Bb Power (5) in the Changes
Where Bb Power (5) sits once the key is named, and what this seat is responsible for while it sounds.
Bb Power (5) is Bb – F. Naming the notes is where a chord chart stops. A tune asks the next question instead, and that is the one this page answers.
Bb Power (5) has no third of its own, so it names no degree until something around it does — which is why it turns up as a suspension over a chord that already has a job rather than as a chord with one.
The guitar seat carries the comp — the changes stated in three and four notes behind whoever is playing the melody, which in practice means dropping the root and playing the notes nobody else is covering — the third and the seventh first, everything else only if it fits under the hand.
Every shape is drawn for EADGBE across 6 strings, the open ones first and the movable ones up the neck after them, and each one plays back so you can hear the voicing before you commit it to a chorus.