1-Firstly, navigate to the directory where Mad Max's save files are located on your computer.
2-Save files are typically found in this directory: "D:\Program Files (x86)\Steam\userdata[userID]\234140\remote" (for Windows). This path is specific to Steam users' games. Normal Windows save game location is : "C:\Users\[user name]\Documents\WB Games\Mad Max\Backup Saves"
3-Once you've found the save file, select and copy the one you wish to share. These files usually begin with names like "GameSave05.sav".
4-You will need to paste the received save file into their Mad Max game's save location, specifically into the "remote" folder mentioned above.
5-You should then launch the Mad Max game and enter it using the shared save file.
6-In-game, you should proceed to the "Dry Gustie" region and participate in a race with the "Archangel" vehicle.
7-By winning this race, you will easily achieve "The Guardian" and "The Messenger" achievements.