When you start separating the screen, you need to start from the top borders and work your way to the center, ungluing the whole screen from top to bottom. Leave some opening tools in to prevent the glass from bonding again to the LCD.

Be extra careful when you get to the bottom because the menu buttons are glued to the glass.

Do not pull the glass just yet, you might damage the cables. Pull the screen from the top to the bottom to the point where you can see the menu and return button cables.