I would like to know how to do this so I can make the c-frame arm go when I press a button. (The arm works if the value is changed manually)
Script that does not change the value
script.Parent.MouseClick:connect(function() game.Workspace.Arm.Begin.Value = true end)
There is something else wrong here. What you are doing should work fine assuming the following:
Lastly if both of those are true try adding a wait as the problem may be that Arm.Began does not exist yet so you are trying to change a non existent value.
while true do
script.Parent.Test.Disabled = true
wait(5)
script.Parent.Testt.Disabled = false
end