This guide is going to be easy to follow (i wish) and there is no introduction needed, the requirements are easy, knowing how to move files from a folder to another

You will need to download the save data, you can find an 100% save file in the link here[mega.nz]
Once you downloaded this the next step is very easy.

FIRST
Locate your savegame folder location
This is for steam, other "versions" (yes, you know which versions) have different locations

"C:\Program Files (x86)\Steam\userdata\Steam User ID Number\254700\remote\"}

Thats the default location, if you have just one account on your computer there will be just one folder, but if you have more than one account maybe you need to find the correct number (or replace the save on both folders).

The folder number is defined by the STEAMID3 which can bee looked up here[steamid.io]

Next thing you are going to do is going to the folder of the game which number is "254700" then a folder named "remote" and you will find a file named "savegame00.sav", you will replace this file with the one you downloaded

And tadaah!, now you have a 100% save file which means you can start a new save on the professional difficulty, ¡congratulations!

Thanks a lot for reading my guide, if it worked for you i would appreciate if you like and add to favorites (and rate) :). (if a link gets removed post a comment.)