Clicking Script help.

Basically I want to be able to hold a key down and when said task is done, it initiates a loop to repeatedly left click the mouse. I don't know anything about pascal and getting really confused with functions. This is what I attempted from various links I searched.

Code:

program CleaningHerbs;
var
   Bingo: Integer;

begin
  while IsKeyDown(VK_SHIFT) do
   begin
    ClickMouse(true);
    wait(random(100) + 50);
    Bingo = random(10);
    if Bingo < 2 then
       begin
       wait(random(30);
       end;
   end;
end.

It could be completely wrong and I'm not surprised. Any help is appreciated.