I dont get how this is the primitive church

So I've been in this church for 2 years and do believe it is the right church. One thing that has been nagging me though is that someone told me this church is christs' church. I do not get how this is true, for we have the Relief Society, the BOM, the Doctrine and Covenants and The Pearl of Great Price.

I still believe fully, but if someone could help me to understand, I would greatly appreciate it. Thanks in advance.

Thank you everybody for everything you showed me. I needed that.