I've been messing around with GUI's trying desperately to get a better understanding of them. I've been trying to get a GUI positioned in the middle of the screen, but it looks different in studio compared to in the real game. Does anyone know a value that is in the middle for studio and the real game?
UDim2.new(0.5, 0, 0.5, 0)
combined with an AnchorPoint of 0.5, 0.5
will put something in the exact middle of the screen. The 0.5s in the UDim2 are for the 'scale' - a scale of 1 means the right/bottom side of the screen and a scale of 0 means the left/top. Changing the AnchorPoint to 0.5, 0.5 tells Roblox that the Position you are specifying is meant for the middle of the object you're positioning (0,0 is top-left and 1,1 is top-right).
If you're not using scripts to position a GUI, it's a good idea to use the Scale system so that it will automatically adapt to whatever screen resolution the player happens to have.