In an ideal world, everyone would use a a registered electrician to carry out any electrical work in your home but some people are keen to have a go themselves. A lot of call outs I get to DIY electrical work is from people who have tried to replace a light only for the light not to work, all the other lights don't work or every time you turn the light it in goes 'pop' and trips your fuse.
A cheap Multi-Meter could save you a headache. If you have some understanding of how a lighting circuit is wired then you can use the multimeter to identify the switch live. With the lights off at the fuseboard, the light switch in the on position, and your multimeter set to the continuity sounder, test between the brown and blue (Or red and black) wires within each cable, the cable the goes to the switch will begin to beep and you can verify this is the correct cable by turning the light switch off which should stop the multimeter from beeping.
Now you know which is the switch live you should be able to wire up the light without any issues!
I created a video talking about a couple of ways a multimeter can be used which you can view here: