Hello, you should know that the notes can also be named with the letters of the alphabet.
A = A - B = B - C = C - D = D - E = E - F = F - G = G - You speak "Gbsus4": means: G flat suspended fourth, so: G flat + C flat + D flat.
We don't have this kind of chord with our instrument, so we will have to complete it with the right hand. If you need help leave a message. @+ Paul