Follow these steps and you will have yourself a nice cracked Fantasy Grounds 3.3.5 Ultimate
(You can also use the steam demo version, follow the same steps, except step 1)
Step 1  : Download the demo here  -  https://www.fantasygrounds.com/home/FGMacInstallation.php
Step 2  : Install the demo, drag it to your applications folder, and update to the latest version through the update in the launcher
Step 3  : While in the updater, go to settings and insert a serial key, in a 5-5-5-5-4 fashion, letters and digits only. EXAMPLE don't actually use this : (DU5K1-5AB1G-H3AD3-DBUTT-FAC3)
Step 4  : Close the updater, and close Fantasy Grounds if it is open.
Step 5  : Right click (Two finger click on MacBook) on the copy of Fantasy Grounds in your applications and left click on "SHOW PACKAGE CONTENTS"
Step 6  : Navigate to Content/resources/Drive C/Program Files/Fantasy Ground
Step 7  : Right click "FantasyGrounds.exe" and rename it to "FantasyGrounds.exe.DuskIsNice
Step 8  : Unzip the "FG v335 U.zip" file you installed from "https://mega.nz/#F!KTYg3IjS!MNj4dWmXZA0cLI4qcqMoDw", open the newly made "FG v355 U" folder.
Step 9  : Drag the "FG v355 U.exe" file into Content/resources/Drive C/Program Files/Fantasy Ground and rename it "FantasyGrounds.exe"
Step 10 : Open Fantasy Ground with the cracked .exe
Step 11 : If you did everything right, in the top right corner it should now say v3.3.5 ULTIMATE
Step 12 : Good job!Congratulate yourself, and do a little dance!
