Issue with cassette installation

[Kramoose]

Hi guys, apologies if this is a noob question but have an issue installing my cassette to my free hub body. Basically the damned thing doesn’t fit! Seems to be the metal bit at the front of the body prevents the cassette going on. Can someone put me right? The cassette is Shimano 9speed and m570 hub. Thanks

 

[dyna-ti]

Is that not the lockring ?

Maybe best you unscrew it first

The lockring holds the cassette in place after you fit the cassette.

 

[Kramoose]

Ohhhhh ffs yes of course. Thanks and sorry for my stupidity.