Master Chen Zhonghua Online Lesson on Mar 30, 2021 - Kelvin Ho
Exercise 1: Use the kua to push the hand out. Shoulder, kua and elbow are one piece. The hand stretches against the shoulder. This is a very practical push hand move.
Exercise 2: Elbow Strike (the elbow has to come out)
Exercise 3: Double Push Hands: Pull the opponent in, Front foot goes forward, rear foot follows. Two hands go out from the dantian with a trajectory. We use the back foot to push.
Source: https://practicalmethod.com/?p=74672