The very first step is to get the clear sound out of the Bansuri. The sound in Bansuri originates from the whirlpool of air in the flute created by your blow. The most important point to remember here is that this whirlpool cannot be created by blowing straight into the embouchure. The only way to create the whirlpool is to blow on the leading edge of the embouchure hole. In a well made Bansuri, the maker would provide a sharp edge for the leading edge rather than blunt wall. For this reason, left handed flutes are different from right handed flutes.
Therefore, you should start with an idea to blow on the leading edge of the flute in such a way that about half the blow enters inside the flute and half escapes out. Till you get the sound right, do not bother to hold the Bansuri in any correct manner. Once we get the sound right, we will focus on fingering. Stand in front of a mirror so that you can see how exactly you are blowing. Hold the Bansuri to align the embouchure at the center of your lips. Make sure that the lower lip covers about 1/5th of the embouchure. The lower lip should be relatively relaxed while upper lip should exert slight pressure on the lower lip so that when you blow, you encounter some resistance to exhaling out.
See the picture here. As shown there, the Bansuri should be aligned with the lips. The shape of air jet being blown out should be horizontally oblong. A circular jet does not produce good sound. The position of the lips should be as if one were trying to say ‘ph..’ rather than ‘oooo..’. The jet of air being produced should not be too wide. If it is wider than the embouchure then we are losing precious air without it helping us produce the sound. If it is too narrow, the sound will not be loud enough. (As a matter of fact, narrow blow is often used to control volume of the Bansuri. Needless to say, it is too soon to attempt that.)
You can gauge how effective your blow is by blowing onto your palm. The feeling of the air jet should be uniform and focused.
Produce sound in this manner till you get prolonged and clear sound out of the Bansuri. It is clearly a matter of a little patience. It is highly unlikely that you will get clear satisfactory sound on the first day. However, in a matter of few days, your effort will pay off and you will be able to move on to the next step.
Did It Work?
Yes? Well done, you can move on to the next step. If it did not quite work, then here are some possible things that you may be doing wrong:
- Is your Bansuri correctly aligned with your lips? Is the center of embouchure aligned to the aperture created by your lips?
- Are you sure you are blowing on the leading edge of the embouchure and not inside the Bansuri? This is one common mistake made by most.
- Is the air jet too wide or too narrow?
- Are you blowing too hard? It does not take too hard a blow to produce the sound. In fact, if you blow too hard, you may produce shrill whistling sounds.
Getting clean sound is a matter of patience. Do not be surprised if it takes you upto a week to do this. Take your time and be patient. Remember that all the time you are investing now is going towards strengthening the foundation and you will reap the benefits of doing this the right way.
 There are significant differences of opinion on this point. Some Bansuri players prefer to ensure that more portion of the blow enters the Bansuri. This produces sound of slightly different tonal quality. The amount of windiness in the sound of Bansuri is matter of preference for many Bansuri players. Some consciously attempt to dampen it. I personally prefer the slight windiness since that makes the Bansuri sound like more natural instrument as opposed to a more perfect mechanical instrument.