Creat backups first to be save!
For all the info go to.
The additional knowledge you need is that for some reason the final Episode 4 prefs.prop gets saved into the Episode 4 folder.
Copy it from "the walking dead 4" to the two locations named in that tutorial and you should be able to use your ep 4 savegames to start ep 5. Worked for me.
/Users/YOURNAME/Library/Application Support/Steam/SteamApps/common/the walking dead/TheWalkingDead.app/Contents/Resources/Pack/