Hi,
A microswitch usually have the common terminal at one end (generally marked "COM") and the other terminal needed is "N.O." or just "NO" (for "normally open").
To calculate the resistor value for a red (1.9V) LED with 15mA on a 6V battery:
(6V-1.9V)/0.015A = approx 270 Ohm (180 Ohm to 470 Ohm will be fine for 6V).