Heldin wrote:i want to create this for only one specific model -> to open and close the hand with a slider in MakeHuman
With a target, the hand will probably not close or open gradually. Or at least, it will not look good.
So if your purpose is to be able to open and close it gradually, then a target will not work.
Heldin wrote:i need help please, to do this with makeTarget.
To create such a target you'd have to export the mesh and then model the vertices to close the hand, then apply MakeTarget as you usually would, taking care to deduct all other relative targets.
You could of course make your life easier and export a model with a skeleton rig. Then you could reduce the modeling problem to a posing problem. After the hand pose is set, the armature modifier has to be applied so that the vertex positions are applied to the mesh.