How to make ScrollingFrame autoscroll?

If you have something like a UIListLayout or UIGridLayout, you can use the following code.

local layout = -- Reference your UI layout object
local scrollingFrame = -- Reference your scrolling frame

local function setSize()
    local contentSize = layout.AbsoluteContentSize
    scrollingFrame.CanvasSize = Vector2.new(contentSize.X, contentSize.Y)
end
setSize() -- Update the size as soon as the game starts so if there is already something in it, it will be displayed correctly.

layout:GetPropertyChangedSignal("AbsoluteContentSize"):Connect(function()
    setSize()
end)

This code uses the GetPropertyChangedSignal event to detect when the total size of the content being manipulated by the UI layout object is changed. This means that if something new gets added to the scrolling frame, it will automatically update.