For letter S: Hiss from the back of your throat like a cat. Not harsh but light smooth and evenly. Take your time with the vibration. It should sound like a cats hiss or like fire.
Letter A: Open mouth wide as in saying "father". Aaaahhhh.
Letter T: Put your tongue on the back of your hard palate where your two front teeth meet your gums. Vibrate the T. It should sound like betwwen a letter T and a Z.
Letter N: Vibrate as in saying the word "no". On your hard palate in your mouth. The sound N should be long and drawn out. It is a nasaly sound.
Letter A: Same instructions as above.
Letter M: Keep your mouth closed. Put your tongue in the position as you would say the word "dog". But you will be vibrating the letter M as in saying the word "mother". The energy mainly should be felt in your head and filling up the head with energy.