What does "building a PAO system" actually involve?

Assigning a fixed Person, Action, and Object to every item in your set — all 52 cards (or all 100 numbers 00–99).

* The 'build it once' end state — one fixed image locked to every item. — Pedros.lol, CC BY-SA 4.0, via Wikimedia Commons. *

It's a one-time construction job: go through each card (or number), and lock in three attributes for it — who it is, what they do, what they hold/use. When you're done you have a complete table (52 or 100 rows, three columns) that never changes. The upfront effort is real, but once drilled it powers fast encoding forever. Build it once, drill it hard, then use it for life.

Go deeper:

• Mnemonic peg system (Wikipedia) — situates PAO as the most advanced peg system.