There should only be , 4 RCAs , [2 sets] front and rea] they are the blue cables plugged into the front and rear low level inputs, [these will not be needed/used so remove completely] the only other lead running from the HU is the amp remote turn on lead. [blue] you have two of them, most likely incorporated into the RCA set, [also not needed]

You should also be able to remove all the aftermarket speaker leads everything running from amp and to/from the cross overs.

All Honda/Acura are factory wired for speakers, front and rear even if car came without radio and speakers, [very few exceptions] these are the speaker leads you will use, connecting the HUs speaker outputs, [4 sets of them, L&R front and L&R rears, Pos.+ and Neg.-, [none of these can be connected together, it will blow the HUs internal amp].You will wire the HUs, [power, acc., ground and speaker outputs] to the OEM radio plug, hopefully the previous owner used a radio harness adapter, although not needed it makes the job easier.
Give me the MM&Y and trim level of your car and I will get you an install guide, but here is the wiring... https://www.installdr.com/Harnesses/HA-Wiring.asp.

Once that is done you will connect the stock speaker wiring to the speakers, the speaker plugs will be in close proximity to the stock speaker locations, on most Honda/Acura the metal terminals can be "de-pinned" from the plugs and used for pretty much any speaker, [even the thin neg.- terminal on most speakers] and you would only use the woofer terminal on the rear speakers, eliminating the need for the cross overs.

FYI, the + and - markings do not technically mean Pos. and Neg, a speaker does not have a Pos. and Neg. terminal, it makes no difference what speaker lead you connect to what terminal, all that matters is that both sides, [left and right] are wired the same way, or they will be "out of phase", the fronts and rears may or may not have to be in phase with each other, [wired the same way, but will have to be in phase with each other] it depends on what the read speakers are used for and other factors, in your case I would try them both ways.
The color coded speaker leads and the + and - on the speakers make it easier to do the wiring, but phasing should be checked anyway, very easy to do, ones wired turn on HU best to use a favorite tune, fade to the front speakers and balance all the way from left to right and center a few times, if bass response is better when balanced to the center then when on the left or right you are in phase on the other hand if bass response is better balanced to the left or right then when in the center you are out of phase.

Checking front to rear phase is a little harder but essentially the same but fading front to rear instead of balancing left to right, and the "center" may/will not be in the midpoint of the fader , but the same thin will happen, at a point near the center of fade control bass response will be best, [when in phase] but again try them out of phase also, one or the other will sound best to you with the music you listen to,

If every thing is working properly you should end up with pretty good "staging", [where you perceive the sound coming from], FRONT STAGE, you should not even hear the rear speakers, they are only there as rear fill, 94