Step 1: Open "Phoenix.ini" in Notepad or another text editor. "Phoenix.ini" is located in your Phoenix installation folder.
Step 2: Edit the values to what you want, 0 = No and 1 = Yes.
WindowMode set to 1 will start Phoenix windowed while setting it to 0 will start Phoenix full screen.
HD resolutions will change the size of the window in Phoenix. If you want the classic resolution MapleStory originally used set ScreenWidth=800 and ScreenHeight=600 otherwise edit ScreenWidth and ScreenHeight to other values for a larger window.
PigMode set to 0 will start Phoenix with Maplestory's original sounds for everything while setting it to 1 will replace all sounds with the Pig mob's death sound.
Step 3: Save and close "Phoenix.ini"
Step 4: Start "MapleStory.exe" located in your Phoenix installation folder and your changes should be applied!