Part 1. How To Hold

I am a left on bottom player. With flutes that have straight holes right or left is up to you. Some larger flutes have shifted holes for comfort. Most of these are oriented for right on bottom players.
Take a look at the picture bellow. I am playing a very large flute with holes offset for right hand on bottom. Notice how I use the pads and middle meaty portions of the figures to assume a correct arm and wrist alignment.

Make sure to relax the arms and maintain a good posture with the back and neck. Take breaks to avoid stress or injury to the body. Remember to keep the middle fingers on the flute at all times as well as the thumb of the bottom hand as these stabilize the instrument and keep strain off of the playing fingers which must remain limber and mobile. Always use the pads of the fingers. Avoid jamming the tips of the fingers into the holes as this is bad practice.
Part 2. Embouchure (how to get a sound)
To get the first sound direct a pressurized air stream at the blowing edge by using the mouth and lip muscles. See the image bellow for an example of how the lips look playing the first harmonic notes. The first harmonic notes become audible with the minimal amount of air. The first harmonic has a range of volume which is decided by how much pressure and air you use; from the lowest sound up to the fullest sound just before the instrument produces the second harmonic which is a higher pitched sound.

You should have the sensation that the air in your mouth is pressurized. You can easily achieve this by forcing more air into your mouth than what can escape through the lips. Using the mouth muscles to form the lips becomes essential in achieving this pressure. To create this pressure you have to hold the lips firm otherwise the air escapes too fast.
Bellow is a photo of the lips playing the second harmonic. The pressure of the air must increase so the lips are pursed even more.

Part 3. The Notes

Second harmonic notes are fingered the same and are played by increasing the air pressure. It is sometimes necessary to experiment with the combination of holes 1 and 2 when playing Ri and Ii in the second harmonic. A difficult or slightly out of pitch sounding Ri or Ii in the second harmonic can be remedied by experimenting with holes 1 and 2. Sometimes with very large wide-bore flutes it is advisable to open both 1 and 2.
Finally, Further Study!
If you are interested in learning more of the traditional notes and music there are very good internet lessons. My teacher Ronnie Nyogetsu can continue instructing you through live Skype internet video chat, personalized mp3's over the internet or by cassette in the mail. He has been teaching long distance for over 30 years with much success.
You can reach him at nyogetsu@gmail.com
So, have fun and thank you for endeavoring to learn this wonderful instrument! Jon~