Just done mine so a few more tips to what Richard has put above.
Read the spec, ensure your using the correct cable types and sizes they are asking for. The practical is straight forward you just have to wire it to the spec. Make sure you know how to SWA an SY with the glands. CAT5 install straightforward again just don't forgot the bridge in the dado trunking.
Safe isolation make sure you go through the steps in sequence. Don't forgot to ask for permission to isolate each time also and don't leave the key lying around, keep it in your pocket or the key safe they suggest (hook on the wall).
Test and Inspect. Straight forward again just need to complete the paperwork upon testing, if you a fair bit of test and inspect should breeze it.
Fault finding, think you have to find 5 of the 7 faults for a pass. Again not to taxing. Not allowed to do insulation resistance and all faults will be wiring faults (no faulty accessories)
Final online exam, open book. If you can read you can pass
Good luck