you go to tourist information, and buy a Jewish map from Warsaw.
See the Warsaw ghetto remains, the cemetery, etc.
The cemetery is a bit out, but all in walking distance from another.
Take a taxi at the airport, but a lot of swindlers, who seem helpful, will rip you off.
As at the little info booth (by the arrivals), what the price is, and deduct 20%.
Bargain down. If the guy gets a heart attack, you just bargain by the next guy and so on.
(If I sound mean, you might need to refreshen your memory a bit. yimach shemom vezichrom milehazkirom !)