How can I drain the water and release the door on my Washing Machine?

Hi
Our Hotpoint 1000 Aquarius de Luxe began a cycle and we came back to the kitchen to find it full of water pouring out of the machine.
We stopped the washing machine but the drum is still full of water and we can't release the door.
Can you let us know what we need to press in the top of the machine to make it safe for us and then what we need to press to be able to make the water drain away and then be able to release the door.
Thank you so much.