how to create two fingers using the pen tool

Hsalim,

You can, Smart Guides being your friends, telling you when you are within snapping distance:

1) Lock the hand path and draw a path from the Anchor Point where the fingertips meet and to the right spot on the back of the hand (ending in a suitable curve which you may create separately afterwards using the Direct Selection Tool and inserting an additional Anhor Point), and Group it with the hand path;

You can further:

2) Apply Pathfinder>Divide to 1) so you get Group with a separate path for the visible part of the visible part of the 2nd finger; or use Shape Builder;

Or you can further (using locking and moving relevant Anchor Points about):

3) Duplicate the path from 1) and use Join to join the identical paths at the back of the hand, then cut the original hand path where the fingertips meet and join each open upper end of the new joined path to one of the open ends of the original hand path so you get one hand path with the separation between the fingers as a double part.

Maybe there are even sillier ways.