I have looked around for this and not found any good answers. I Just pulled python from git and built it on Windows 10.  The python.exe file works fine when in the build location but, if you copy or move the folder you built into you get the following error upon running python.exe:

Fatal Python error: Py_Initialize: unable to load the file system
  codec LookupError: no codec search functions registered: can't find
  encoding
Current thread 0x000060c8 (most recent call first):
   .\python Fatal Python error:
  Py_Initialize: unable to load the file system codec
  ModuleNotFoundError: No module named 'encodings'
Current thread 0x00004f50 (most recent call first):

This is strange cause if you run python from the build directory
D:\Users\brazg\Documents\GitHub\cpython\PCbuild\amd64 it runs fine.
I would like to know why python.exe doesn't run if the amd64 directory is moved out of PCbuild.
As a side note I cannot find any information for setting up the Python root folder after building from source.
This is an answer from the perspective of someone that hasn't built python from source before.
To answer my own question, what needs to be done after moving the Python binaries to a different location out of the cpython\PCbuild is you need to copy the Lib directory from the pulled sources because the encodings directory is in cpython\Lib.
Even though you the build is in cpython\PCbuild\<build directory> it still reads from cpython\Lib which makes sense but, I think should be made more clear in the official python documentation.
If you copy the amd64 directory to a new location you need to copy the cpython\Lib directory into the amd64 directory.  You can also delete all the .exp, .lib and .pdb files that were built with python from running build.bat. As they are all the compiler's linker and debug information.
I wish it was made more clear that cpython\PCbuild\<build directory> read up to cpython\Lib when run.
No modules named 'encodings' if python 3 directory is moved after building from source code