So, my F100 came without the original ignition switch and i plan to install it, i just bought the part, its this one

It also brings the front nut that screws into it. Problem is, i never seen the original one installed and i have no idea how to put it. Originally i thought that just putting it from behind and screwing it would be it, but it turns out it is not, it hangs there all loose, I´m apparently missing something.
I saw some other switches that come with a big spring, could this be the piece i´m missing?
Thanks a lot, greetings from Argentina, and sorry for my bad english!