Hello and welcome.
Here is one method of many.
I borrow from the image itself!
(Please understand that I will do this very quickly for demo purposes, so it's not perfect)
Make selections of the coat using any of the selection tools, copy it to it's own layer (Cmd/Cntrl + J) and then move them.
Note: Here I have lightened the borrowed parts so you can see them.
I used the Move Tool and Free Transform to position.
Left Side
Right Side
Both
Add layer masks to each of the borrowed layers.
Use the Brush Tool on the layer mask to start blending.
Note: I still have the borrowed layers brightened for visibility.
This is without the brightening.
Lastly, I used the Brush Tool to continue blending.