Generally speaking, after rinsing the pig's feet with water, pour them into an electric pressure cooker and press them for about 15-20 minutes.
Also or after the pressure cooker bared gas, high heat for 15 minutes, change to low heat for 10 minutes, then simmer for 20 minutes.
If you want the pig's feet to be more tender and melt in your mouth, you can extend the pressing time.
Be sure to cook the water to boiling over high heat first, then turn to low heat and slowly press it.