The basic meter for the 2 pattern is 2/4. It can also be used in C, C (alla breve), 2/8, 4/8, and 6/8. It can also be used for 4/4 and 12/8 in fast tempos, and can appear in patterns where the meter is uneven e.g. 5/8 and 7/8.
In the 2 pattern, the hand drops down to the first ictus, and its rebound curves out towards the right and upwards. It then retraces its path, swinging back downwards and inwards for the second ictus. As it rebounds upwards, to the top of the pattern again, it becomes the upbeat that prepares the next downbeat. It’s similar to the shape of a candy cane. Assuming you are leading with your right hand, a simple description is: down and out, in and up.
Using a 2 pattern, conduct “Bobby Shaftoe”. Although this is not live conducting – and you’ll be following rather than leading – it is helpful for establishing the pattern. If possible, try it out with singers.