The chord Bbsus4 that is shown here contains the notes: Bb, F. The root of the chord is Bb (The lowest sound - the bass - is BB). The scale from which the chord is derived is Suspended fourth chord (1–4–5), and the degrees of the scale are: 1, 4, 5.
To play the chord Bbsus4 shown above, place your fingers as follows:
On string number 4 (the thickest), on fret number 3 with finger number 3 (ring finger)
On string number 3, on fret number 3 with finger number 4 (pinky)
On string number 2, on fret number 1 with finger number 1 (index finger)
On string number 1 (the thinnest), on fret number 1 with finger number 1 (index finger)
Finger numer 1 presses multiple strings as a barre.