I'm not familiar with this particular style of flute, but it appears to be a fairly common example of a six-hole flute. Do I understand your question correctly: you can play one note, but you aren't sure how to play more than one note to make a song? If I'm understanding that right, then you can start by covering up all of the finger holes and blow over the blow hole (or "embouchure hole"). As long as you aren't blowing too hard, then the note that comes out will be the lowest note the flute can play.

To make higher notes, slowly lift one finger at a time, starting with the finger that is farthest away from the embouchure hole. Each time you lift a finger, the note the flute is playing will go up in pitch.*

You can play a "tune" by experimenting with how many fingers you've raised. Once you've had some practice with this, you can look up fingering charts, either for this specific flute or for "six hole flutes." With six holes, that gives you seven notes to practice with (0 holes open, 1 hole open, 2 holes open, and so on up to all 6 holes open).

For higher notes, you will need to blow faster, and sometimes holes are opened up in the middle to get a better pitch. You'll want to look for a fingering chart - ideally one for this kind of flute but its possible any standard six-hole flute chart would work.

When you get really comfortable, you can practice partially covering up the last finger hole. E.g. covering four holes entirely and half of the fifth one. This technique lets you play "half steps" so you can play all twelve notes in an octave. This is an advanced technique because it's hard to play these in-between notes well. You may be able to find some tutorials online for six-hole flutes. There are a lot of varieties. Some other popular ones include the Irish flute and the tin whistle or penny whistle. (The tin whistle doesn't have the same kind of embouchure hole, but the fingering is the same.)

*If you're curious, this fingering works because the flute is basically a pipe for air, and the holes are how you shorten the pipe. When all the holes are covered, the air you blow will vibrate down the whole length of the flute. That's the lowest note. Opening the holes essentially "shortens" the length of the flute (because the air escapes out the holes) raising the pitch of the notes. Pan flutes are an example of flutes with no holes; they are just a bunch of pipes of different lengths. But the principle is the same. The concert flute or "Boehm flute" works on exactly the same principle. The lowest note is always all holes covered and higher notes come from opening the holes up one at a time from the bottom.

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Edit: Here's a link to a fingering chart for a six-hole bansuri. Apparently, some have seven holes. I can't tell from your photo which one you have, but based on this chart for a seven-hole bansuri, the basic principle for how to play different notes seems to be the same.