OP: I feel your pain based on a flashback to my first system. So many cables and components, “wtf, why didn’t I keep that all-in-one stereo console?”
Take a deep breath. Start backwards with connections. Speakers. Set them up where you want. Speaker wires: connect them to the speaker lugs, keeping track of which speaker lead is “+” and connecting it to the corresponding “+” speaker terminal lug. Repeat that process for the “-“ speaker wire and speaker lug corresponding to the “-“ terminal.
Amo, integrated amp or receiver: connect the speaker wires from the right speaker to the corresponding speaker output terminals, with “+” speaker wire going to the “+” output terminal of the amp, integrated amp or receiver and with “-” speaker wire going to the “-” output terminal of the amp, integrated amp or receiver. Repeat process for other speaker wire.
Congrats! You’re half-way done!
Next, let’s tackle the sources (record player, CD/DVD player and or streaming device). These will be linked to the right and left inputs of your preamp, integrated amp or receiver. One source per input. Now if you have a separate preamp and power amp, then you will need to connect those together. One set of interconnects usually is required, leading from the right and left outputs of your preamp to the right and left inputs of your amp. The interconnects needed depends on the types of inputs and outputs on your sources, preamps and power amps (or integrated amps or receivers if you don’t have a separate preamp and power amp). Those are RCA plugs for “unbalanced” interconnect (most commonly found in home stereos) and XLR plugs found on “balanced” interconnects.
Turn on the set up with the volume fully down (or muted if there is a mute switch). Gradually crank up the volume with no source on and listen for hum or a buzz sound. If you hear that, then turn down the system (or off) and grab a friend to help you resolve the hum or noise issue. One usually needs to attach a ground wire from the system to a power strip ground to resolve the hum or noise. There is plenty of threads here that can help you rectify these and other issues you might encounter.
About all the wires, cables and cords. Try to keep the power cords free and clear of the rest.
That’s it! Enjoy!