I have old wiring for a light fitting

Question

3x red together

2x black together

and 1 black on its own where do i put these in my new light fitting?

Answer 1

This is a Home done job and does not meet code.  Does this have three way switches?  You will have to trace to the switches and find out what is coming from there.  Hire a professional, be safe.

Answer 2

Where are you?

Color codes differ from country to country.

Answer 3

You should also have a white wire. White to white, ground to ground, the single black is probably the one for that light fixture.