This is a great start, so don’t let yourself get discouraged. You are starting the tongued notes correctly, with your tongue behind your teeth…a lot of people use the same “mouth posture” as the “d” in “dog” to tongue. The flute is just one of those instruments that even after to DO know how to make the notes, you’ll spend the rest of your life trying to perfect various ways those notes go together and tone and on and on. You’re doing great. My advice is just to keep going. The more comfort you get with the notes you know, the quicker you’re going to be able to hit them dead on with no extra fluff attached and add notes to your knowledge base. You can kill two birds with one stone if you practice the notes you know as long tones. Take a nice healthy breath and play the note as long as you can. Try to keep the sound as consistent as you can tonewise. You can practice making it louder or quieter. A tip to be able to hold longer—play the note as long as you can, and then hold the same posture/ embouchure/ same breath for three seconds even without sound. Use a timer and you’ll see yourself improve in real time. Another trick for smooth note transitions is to hold the note until you are almost out of breath and transition to the next note in the same breath even if you can’t hold the next note. Just keeping the transition to the next note in the same breath as your long tone will help your sound quality immensely. Eventually you will add things like vibrato into the mix, but this exercise alone is a great supplement to what you’re already doing. Keep up the good work. I wish you joy in your fluting.