So hopefully you have downloaded OSConfig from GitHub and are now ready to add to MDT.
The ZTIOSConfig.wsf file should go in your %ScriptRoot% directory
The OSConfig directory from the GitHub download should go in Applications. Alternatively, it can be placed in %ScriptRoot%\OSConfig without making any additional modifications
In your MDT Task Sequence, add a Run Command Line step and run ZTIOSConfig.wsf using cscript
Additionally you will need to make a change in your Unattend.xml file you will need to add an entry in your RunSynchronous section. This will allow OSConfig to run on the first reboot from WinPE
Additionally, delete any .gitignore files that were downloaded as part of the Zip and do not include them in your OSConfig directory