Changing plugs on a ford focus 2.3?

When you change the plugs on a 2005 ford focus 2.3 motor is there anything special you need to do with the spring. I removed the coil w/ the 7mm socket and disc. the wire lead to the coil removed the plugs and reinstalled but my question is when installing the boot and springs to the coil is there anything special one must do? I just put the spring into the coil tight and then slid the boot (spark plug wire) and pushed it down and rebolted it but my question is how do I know that the spring is far enough down on the spark plug? thank you so much for anwering my questionChanging plugs on a ford focus 2.3?Every thing sounds ok. The vibration of the motor when started will cause the springs to expand into place.