To experience Pompeii fully involves two stops. One is the excavated city south of Naples and the other is the National Archaeological Museum in Naples. Pompeii is mostly a barren ruin of streets and walls. Most of the "good stuff" has been moved to the museum. The easiest way to get to Pompeii (and Herculaneum) is by train. I took the metro from the stop next to the Museum to the Garibaldi main train station and spent 30 minutes wandering around, asking and wandering some more to find the platform for the trains that take you to the ruins. As the Italians say: "You down there, go left and then go right and walk a bit and you'll be there..."

Anyway I did find my way.
The weather was nice, sunny and warm. Having a map, paper or digital is important to find your way around. Once inside you can wander around all you like. I entered through the Marina Gate (lower left).
The earliest settlements date back to the 8th C BCE
The Greeks showed up about 750 BCE and Pompeii became a safe port of Greek and Phoenician ships.
The Etruscans took control about 500 followed the Samnites in 320 and finally Rome in 290 BCE.
The current city walls date back to the Samnite period and 2nd Punic War. The city flourished under roman rule and the estimated population in 79 AD was between 11,000 and 20,000. As the city grew, fancy villas were build by the wealthy outside the walls: Villa of Diomedes and Villa of the Mysteries are examples. The oldest parts of the city are to the left side (west), closer to the coast. As the city expanded, the street plan became more organized. Currently, the city is 700 meters from the shore. In Roman times it was at the water's edge.