How to connect audio interface to powered subwoofer and powered monitors

I recently fixed my audio interface and would like to be able to connect it to both my powered monitor speakers and powered subwoofer.

I apologize if anything seems obvious, I wasn’t able to find anything helpful through searching the sub or the internet.

The manufacturer manual of my interface (Focusrite Scarlett 2i2) suggests connecting the line outputs to the subwoofer (JBL SP-150) and then the subwoofer to the speakers (M-Audio AV40 monitors, no subwoofer out).

My confusion lies in connecting my audio interface to the powered sub: the Focusrite interface has a L/R TRS out but my subwoofer has both a mono RCA input and a L/R input for speaker wire labeled "from receiver."

Should I connect the interface to the subwoofer using a mono TRS to RCA cable and then the speaker wire outputs on my sub to the RCA inputs on my monitors?

Or should I just connect the interface to a mixer and then connect that to the speakers and subwoofer?

Thank you for reading through my post, any and all help is appreciated.