I have just been explaining to several others whats going on. This is primarily a breathing exercise. As a newbie you have not yet developed your breathing , lungs and mouth muscles. This dosnt happen overnight but it does happen. Try following the basic beat patterns on the app. Jut play with the holes 3 5 and 6. don't plays hole 4 . Your low end scale is 5,6 and 3
Watch the videos where I talk about the beat is the street, You should be able to follow the beat In the low notes and just play around with the lower 3 notes. A common mistake is to try and play a full scale on one breath. this is difficult for new players as your breathing isn't up to scratch Make sure you have full lungs when you start on hole 3 and go up to hole 1, Follow the beat fill your lungs at hole 1 then go back down the scale.
Its important to play to the beat at this stage, so set little patterns.
I.e. 5 5 6 5 5 3
play this to a basic beat, Do it until you feel that beat.
Then try 3 3 5 hold the 5 note for a couple of beats then move into 3 3 2
at the start of each pattern make sure you fill your lungs.
As you develop your breathing you will find that the Saxmonica reacts very easily . You won't need to breath nearly as hard and slowly but surely you will develop your skills.
At the start your mouth gets pretty tired but this goes away in a few days and muscle takes over. Don't over play it for the first few days.