You can take either the Hudson or Harlem line on Metro-North to Grand Central Terminal. From there, you have a few different subway options. The most direct subway option (in my opinion) is taking the shuttle train (a grey circle with an S in the middle) to Times Square-42nd street (only one stop). Then, find the Van Cortlandt Park-242nd Street bound (northbound/Bronx bound, if you ask someone) 1 train (it's a bright red circle with a 1 in the middle). Go 2 stops and get off at 59th St.-Columbus Circle. When you get above ground, orient yourself (Columbus Circle can be overwhelming once above ground). Walk along the park with the fountain/statue on your left and along W 59th street. After walking along Central park (with it on your left) for 9-10 minutes, you will see Center drive. Follow the directions on the Schedule page from there :).