Getting WinPE images

You'll first need to download and install the Windows Assessment and Deployment Kit:

Once that's done, go to the path where you've installed the ADK (on x64 it's C:\Program Files (x86)\Windows Kits\10\ by default) and you should find the winpe.wim image in the \Assessment and Deployment Kit\Windows Preinstallation Environment\ARCH\en-us\ directory (replace ARCH with either arm or arm64).

Alternatively, you can open the Deployment and Imaging Tools Environment as administrator (the search bar will help), and type the following command:

copype ARCH path

Replace ARCH with the desired architecture, and path with the destination directory.

The image can be then found in the path\media\sources\ directory.