Denis,
The example I have attached is based on your original image you posted of your problem.
I made a lot of assumptions like I'm assuming you have a clearance hole between the legs of the rectangular part and the pin and that you are only constraining it at the ends of the pin, material?
I added surface regions for each contact and for each displacement constraint.
I have added 3 springs to stabilize the parts so the analysis can begin from a know starting point.
I have added contact to each of the fingers
I constrained the ends of the pin
and applied the material to each part.
If the pin has a press fit you will need to use a deferent model setup than what I have provided,
See if the attached files help,
Don Anderson