Hi ebbn
Welcome in the family!!!
All the instruments are coming with 1, 2, 3 or more layers. This means that the same articulation (for example sustain) of an instrument is recorded in p, mf and f (layers). If you play your sampled instrument the Vienna Instrument will choose between these layers depending on the midi velocity.
In case of having just two layers the switching point is between the velocity 88 and 89. So the sound changes between these two velocity values (sometimes extremly in connection with brass instruments).
There is a function called X-Velocity. You can blend with it in a more or less softer way between the two (or more) layers. This possibility is helpful specially with slow played music. Read more about here... ( 24A - 24C). Finallly you draw a dynamic curve with X-Velocity so to say.
With faster pieces it is OK to use the velocity directly from the keyboard.
If you are new to "music played with samples" take into account that this is mainly a matter of "making compromises". Nevertheless there are nice results possible... 😉
Happy Music
Beat Kaufmann