How to get to the venues:
On the map the central station is labelled 'Centrale FS'. To get from there to the Sacristia del Bramante (located alongside the Church of Santa Maria delle Grazie, home to the Last Supper) - you need to take the south-bound green line, the 'Metropolitana Linea 2' and get off at the Cadorna stop, 'Cadorna FN' on the map. Any and all south-bound trains on this line will stop at Cadorna, so jump on the first one. The station mentioned on the signs, and on the front of the train, will be the ultimate destination - usually the last stop on the line.
If you're coming from elsewhere in the city then note that you can also get to the church on the red line, 'Metropolitana Linea 1', and you'll be alighting at the 'Conciliazione' stop.
The Pinacoteca Ambrosiana is in the centre of town, and you can alight at either the Duomo or Dante Cordusio stops. The distance between the two venues is a little over a kilometre.