How to solder the plug from the headset to the speakers?

Question

Cables and wires

Hello! Faced with the need to solder a new plug to the cable of my SVEN stereo speakers. The plug on the end that is now connected to the speakers has a standard TRS connector. On the other hand, we have a red and white cable, and next to them there are 2 more cables without insulation, earth, as I understand it. There is also a mono screw plug and a TRRS plug that I borrowed from a non-working Xiaomi phone headset.
Firstly, please tell me where to solder which wire from the speakers to the plug from the headset
and secondly, how can you connect a screw mono plug, because if you throw red and white wires on the "+" and "-", the sound is somehow not like that (there is no bass, and in general the sound is bad, although distinguishable). If you throw more earth at them, it's even worse. BUT if you throw the 1st or 2nd earth cable into ONE of the channels on the plug, the sound on the speaker, where the earth is not thrown, becomes normal, but the second speaker falls silent. If anything, the mono plug is connected to the PC.

Answer 1

1. One photo is several orders of magnitude more informative than 100 words.
2. Taking a photo and attaching it to the question is an order of magnitude faster for me than typing 100 words (although I personally type with two fingers).
But I still fought my way through your ornate formulations. You want to replace a 3-pin plug with a 4-pin one, right?
If yes, then everything is elementary - you need to stupidly parallelize contacts 3 and 4, and connect them to a common wire (ground, screen). In my opinion, this is so obvious that I do not understand what could have confused you.