If you want to take this a step further click on edit pose. This will focus in on the preview hand and allow you to create custom poses your hand will mimic once you grab an object.
Manipulating the preview hand joints
Once you are done posing the fingers of the hand to your liking, look over to the inspector, you will find the pose data component.
Pose Data component
Apply and save changes. The editor will prompt you to choose your file location and name. After doing so, you can close the grab point window.
Grab point component with marked grab pose
Your newly created grab point should now be assigned to the grab pose field of the grab point component!