How to reposition SSD mounting bracket on m2 slot?

 Hi,

I am using Inspiron 15 5510 model and want to add 2280 SSD to M.2 slot one.

I saw the service manual but a little different with real laptop.

Service manual guided like below way to move bracket. 

Than i tried to move bracket, i cant. that is fixed. looks like not removable

And if i remove that, how do i put here?

Please let me know how do i reposition mounting bracket.

Thank you.