So I have been having an issue for a while with ui sizing the same for all platforms.
I want to scale a image label for 1/2 off the screen but I don’t know how to do this.
I have seen people talk about UiAspectRatioConstraints and I have tried the properties but it’s not scaling correctly.
Please explain in detail on how to do this!
If you want something to always be half the size of the screen, use Size.Scale instead of Size.Offset {0.5, 0}, {0.5, 0} means middle of the screen for all devices, but don’t forget to set the anchor point to 0.5, 0.5 which position relative means center of the element. Anchor points go from 0-1. An anchor point of 0.2, 0 means position this ui element relative to 20% of it’s x value from the left because ui elements by default anchor at 0, 0 which means top left. 1, 1 means bottom right.
It works! Thank you so much! 
If you want it on the left middle of the screen on all devices, you can Anchor at 0, 0.5 and set the position to {0, 0},{0.5, 0} which means no change on the X axis, but halfway, or 50% of the way 0.5, down the screen.
Make sure you can control the offset of the gui’s you have.
This video can explain it for you. - Roblox Studio | UI Scaling Tutorial [How to Fit a UI on the Screen on any Device] - YouTube