A beauty, isn’t she? Very light and open.
The Bb11 holds a “sus 4” like tension, which is resolved in the next bar.
It’s basically the same tension and resolution you create by playing a campfire D chord and adding your pinkie on the 3rd fret of the high E string.
The sophisticated 11 sound is achieved by keeping the tonic on top and hiding the sus4-to-major-3rd-movement (D# to D) in the insides of the chord.
Move it up 5 or 7 frets to the corresponding IV and V chord positions.
Dazzle your competitors when you play this one!