zinedine
Striker
If the old rose had a wire for a pendant hanging from it your new light just goes to the two connections the pendants wires were connected to.Pretty much this, old ceiling rose and the new light just needed live/neural. At the ceiling rose the cables weren't labelled and the neutral wasn't marked as switched live, but it was at the switch itself.
I've fitted a new switch (old one was a dimmer) and it's now working...for now!
You should have marked all the wires or took a photo but a bit late now. If you've got a multi meter you should be able to find out what is what. Put some red or brown tape around the switched live at the rose and the switch. Make it easier for future changes.