Please help me understand how to use CREF and SREF!!!

I have tried everything and nothing im doing is working. Im just trying to successfully use the CREF and the SREF in one image. For i test i tried this:

samurai slashes sword --CREF https://s.mj.run/lxi9rsjqI88 --SREF https://s.mj.run/8fVCR1rple4

and midjourney says this:

Invalid parameter

Unrecognized parameter(s): --CREF, https://s.mj.run/lxi9rsjqI88, --SREF, https://s.mj.run/8fVCR1rple4

/imagine samurai slashes sword --CREF https://s.mj.run/lxi9rsjqI88 --SREF https://s.mj.run/8fVCR1rple4 --s 50

What am I doing wrong? if someone can help me understand what i need to do for it to work i would very much appreciate it. Im using discord so i dont know if that matters vs using the website directly