Lspaddo

Ok, giving this a shot. Hopefully it doesn't go in to the void. I have a Panasonic SA-XR45. When I first got it I had a TV with compatible technology. The surround sound worked for the TV audio, tuner audio, CD audio - even a VCR! Now I have a TCL Roku TV (model 40FS3800). It has an SPDIF audio output, RCA INputs, (2) HDMI jacks (which I don't know if they're outputs or inputs) an ARC audio out and a headphone 3.5mm audio out jack. I have mansged to get TV audio to come through the surround system via an optical cable, disabling the TV internal speakers and choosing PCM on the TV audio settings. However it's only utilizing 2 of my five speakers. Bummer! I've done a fair amount of googling. My head's about to explode. What it SEEMS is in order to get full use of the surround system I should be using this thing (or something very much like it): J-Tech Digital HDMI 1.4 Switch Switcher Box Selector 3 in 1 Out Audio Extractor w/Optical SPDIF & RCA L/R Audio Out & IR Control Supports ARC, MHL, 4K, Full 3D, 4kx2k, 1080P (Support Apple TV 4Gen) found on Amazon. I have cables of all kinds. I AM NOT A TECH-HEAD whatsoever. It's miraculous I've gotten this far. Is this $39 thing what I need? If it is, how exactly (I mean I need step-by-step) do I hook it up? Will I need to choose certain TV audio settings? Will I be able to get surround sound for Netflix, Youtube, Amazon Prime video (I stream 99.9% of the time) using this thing? If anybody can assist please keep your explanations and instructions basic, basic, basic, basic. Thank you!!! I really want ALL my speakers to be in use for my TV audio.