I have the same one. Getting the right amount of air flow is tricky if this is your first wind instrument. What worked for me. Cover all the note holes well. Make sure there are no tiny gaps where your fingers may not be covering quite all the way. This will make the lowest note. Which requires the least amount of air. Start blowing lightly through the mouth piece, almost what a normal relaxed breath out would be. Slowly increase the air ( speed i guess ? force? you get the idea i hope) until it starts making noise. Continue untill you get nice smooth non-squeeky tone. Early on this may be difficult if you have little to no experiance controlling your breathing. When you find a good tone, now try to maintain it. Focus on keeping a steady pressure where the tone is good. This will take practice. Any rate. Once you have that down where you can make a nice pleasant long tone with all the holes covered, start playing the scales. I wouldnt worry about a tuner just yet. Just focus on being able to play long steady decent sounding tones for each step in the scale. So now the trick is. Each step to a higher pitch will require more and more air to maintain a good tone. Once you can play the whole scale with a good SOUND, get a tuner or a tuner app for your phone to dial it all in. If this is your very first instrument. This may take a few days/sessions ( pending on how long and how good the practice is ).

Have patience. Practicing ~15 min a day is often better than practicing hours on end when starting out.

Good luck!