How to let players select hair color from an RGB GUI?

local function onClicked(playerWhoClicked)
    playerWhoClicked.Character.Hat.Part.Mesh.VertexColor = Vector3.new(1, 0.6, 0.6)
end

script.Parent.ClickDetector.MouseClick:connect(onClicked)

This is a very simple script I've written where if a player clicks on a block, the color of the hair they have on (under Hat) changes (in this case the color is pink). I've found a couple of RBG color pickers (this one, for example: https://www.roblox.com/library/67612862/Color3Picker-GUI) and I was wondering how to get the RBG values from a GUI like I posted, and set it as the Vector3 value so a player can essentially set a custom hair color with an RGB slider. Eventually I want to try to make my own GUI but for now I would like to learn with a premade one.

I honestly don't know how complicated this is, but I've searched everywhere to figure out how to do this and haven't had any luck despite the fact that many popular games have this option. I'm very new to scripting and especially to GUIs.