Making a derma menu?

How do you make a derma menu with buttons with functions and how do you make it pop up with a key?

Start here: http://wiki.garrysmod.com/?title=Derma_Tutorial1

[lua]
function DERMAMENU()

local Requested_Derma_Menu = vgui.Create(“DFrame”)
Requested_Derma_Menu:SetSize(300,170)
Requested_Derma_Menu:Center()
Requested_Derma_Menu:SetTitle(“Requested Derma Menu”)
Requested_Derma_Menu:MakePopup()

local Button_11 = vgui.Create(“DButton”, Requested_Derma_Menu)
Button_11:SetSize(289.5, 42)
Button_11:SetPos(4.5, 26.5)
Button_11:SetText(“Button 1”)
Button_11.DoClick = function()
–custom code here
end

local Button_22 = vgui.Create(“DButton”, Requested_Derma_Menu)
Button_22:SetSize(289.5, 42)
Button_22:SetPos(4.5, 73)
Button_22:SetText(“Button 2”)
Button_22.DoClick = function()
–custom code here
end

local Button_33 = vgui.Create(“DButton”, Requested_Derma_Menu)
Button_33:SetSize(289.5, 42)
Button_33:SetPos(6, 119.5)
Button_33:SetText(“Button 3”)
Button_33.DoClick = function()
–your custom code here
end

end
concommmand.Add(“RequestedDerma”, DERMAMENU)
[/lua]