Yeah the docs don’t really explain it but that bottom part in you’re last pic (in the initial post) defines the width of the UI. The idea behind it is you want the UI to animate from 0-100 (100 is the arbitrary length that they decided the UI should be) which can be easily accomplished by using how long the button has been held down for. However you want the value to be at 100 when the timer reaches 0.75 so therefore you need to normalise the time value (so its 1 at 0.75) this is done by dividing 0.75).
Now you have a value that animates from 0-1 in 0.75 seconds so all that’s left is to multiply by the length you want the element to be in the end (in this case 100).
However here is where the issue comes in just above this you’ve told the UI to be in the middle of the screen but you just told it to expand 100 units beyond this when fully animated, anyway all you’ll need to do is subtract 50 from the Screen X Value (or the final width divided by 2, 100 / 2)
Anyways, shameless self promotion, I cover this and how to create a cool little circle UI animator for this (just like the oculus one) in my upcoming book 