grab few books on the techinique if you can, there’s enough material to be find on the forum search under resources.
The basic pdf is good enough to get going. Read that PDF, create few memory palaces and daily remind about them.
Create a 0-99 two step PAO system as a starting point and then try to remember number plates and put each of them at the loci’s at your memory palace. (the achievement should be enough for you to practice every day.)
You should then come to a point where you see the numbers in PAO system, which means you have successfully remembered all from 0 -99. It took me 2.5 months daily practice to remember the complete PAO system. But still I’m scared of losing it so, I practice it at least twice a day.