Remove the trigger guard as described in numbers 7-9-10. You will see the hole for the spring, may still be some in there. You will need to make a slave pin for reassembly, a nail about the diameter of the trigger pin cut to length so that it will go through the trigger guard but not stick out the sides. Be careful not to bend the spring, only compressing it. You can now put the trigger guard back in the receiver. Line up the hole, put in the trigger pin and drive the slave pin out.
Hope this helps,.