To compile the extender, you need another working PC running Windows 7, and then install the WDK 7.1.0 on that Windows 7 machine, and Notepad++ for editing the NTOSKRNL Emu_Extender source code files before compiling.
And you also need Dependency Walker x64 to check for the missing dependency functions, and CFF Explorer to modify the PE-formatted files (e.g. .exe, .dll, .sys, etc.).
First, open CFF Explorer, and load the driver file (.sys) you're going to install. Then, go to the Optional Header section, and change all the minor versions to 0000 (if the major versions are 000A, change every of them to 0006). And then in Import Directory section, rename ntoskrnl.exe to ntoskrn8.sys. Save and overwrite the file, recalc the checksum in Rebuilder section, and save again. Don't forget to make a backup copy before modifying in CFF Explorer (rename xxx (2).sys to xxx.sys.bak). To check for the missing functions, open Dependency Walker, and load the previously modified driver file. If there are no critical issues, your driver is now ready to be installed.
Suggestions: If the driver file (.sys) is signed with certificate, you need to delete the certificate first using delcert.exe before modifying it to avoid corruptions or malfunctions. Here is the link:
https://forum.xda-developers.com/attachments/delcert-zip.105230/