1) Open both of the images in separate tabs as shown.
2) For this tutorial, I will be blending Mr. Bean's face with Trumps so first I will cut out his face using the Lasso Tool. *Make sure there is no feather on the lasso tool*
3) I will select the move tool and press Control + C to copy the selected face. THEN I will go to Trump's face and press Control + V to paste it
4) I will then make the opacity of the face somewhere between 50% so I can line up the eyes with Trump's eyes or fit the face in with the head. Once I'm done, I will set the opacity back to 100%. *MAKE SURE TO DUPLICATE THE LAYER OF THE IMAGE YOU'RE PUTTING THE FACE ON* (In this case, I will duplicate the layer of Trump)
5) I can see the some of the face interferes with the hair so I will use my eraser tool with a hardness set to 90 to 100%
6) Make sure you have the face layer selected in this case is Mr. Bean. I will go to the top and click Select and then Select All.
7) You should see the selection bar around the image as shown in the first picture. I will then use the move tool and move the face to the right a small bit and then back to where it was. Once I do that, the selection bar should be around the face as shown in the second image.
8) I will then go to Select at the top and click Inverse. You should see the selection border around the face as well as the whole image (Second Picture).
9) Click Select again at the top and click Modify -> Expand. Set it to 6 pixels. After that, Click select at the top again and click inverse so that only the face is selected again.
10) Select the second layer and hide the first and last layers as shown in the picture. The face should still have the selection border around it.
11) Press Delete on your keyboard and then unhide the other layers.
12) Select the first two layers. (Hold Shift and Left-click the other layer to select both)
13) Go to Edit -> Auto-blend Layers. Make sure to have the settings as shown below.