We are located in the Psychology building which is Building 420 on the main quad, with the oval behind you the building is to the right. We are on the 3rd floor of Building 420, South wing (towards your left as you enter the building from the oval) of the Department of Psychology, Building 420, Stanford University.
The easiest parking garage with visitor parking is “Roble Field Garage” which google can tell you how to get to. It's a 15 minute walk from the garage to Building 420:
After 4PM on weekdays and anytime on weekends you can park in any areas marked A or C (except the oval, which is enforced until 6PM on weekdays) for free as enforcement times are only between 6AM and 4PM Monday-Friday. You can also find spaces in Parking Structure 1 (the area marked in purple in the map below) behind the Cantor Art Center. The parking structure has machines where you can pay by credit card for parking. It's a 10 minute walk from the parking structure to Building 420 (orange in map).
You can take Cal Train to Stanford → get off at the Palo Alto station and walk up Palm Drive to the oval and Building 420 is just to the right of the top of the oval. Note that Cal Train from the airport, well, sucks. You will likely have to take BART one station north, then switch trains to go one station to the south and then switch again to get a Cal Train that will take you to Palo Alto. Yes, this is the line that expects to become the Bay Area backbone of the futuristic bullet train system that, er, some other countries have had since the 1960's. Welcome to Silicon Valley - home of America's technology revolution. I recommend Uber from the airport.