That's great
Cable 1 is the switch cable.
If you have some masking tape or white tape (not red, black, brown, blue or green tape) write "Switch" on it and attach to the cable 1 sheath.
Put some red tape or sleeving round Black 1. It is the "Switched Live." It is very important that you do not connect it to any of the other blacks.
You will now need a connector block. There might be one in your light fitting. If not, buy a strip at your hardware store.
Put all the red wires in one terminal.
Put Black 1 in a separate terminal.
Put blacks 2 and 3 in one terminal.
Sheath all the earths in green/yellow and put them in a separate terminal (or an earth stud if there is one).
You lighting fitting might have a brown, a blue, and a green/yellow wire coming from it. If so, put the brown in the terminal with Black 1. Put the Blue in the terminal with Black 2 and Black 3. Put the g/y with the other earths.
Stand back.
Turn on the power.
Operate the light switch.
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