i click on the "strengthen skill" bar and it gives me basic 1 questions every time. How could i update that
Strengthen skills will give you whatever words have weakened and need to be practised. The more of the tree you've done, the more it has to choose from.
The more you use it, the more it gets to know you, and the more it learns that you can do those questions easily, the more it will give you different words to practise.
But you only have done a few lessons, if I saw it correctly. In addition to what MargaretAl180930 wrote, go ahead and the amount of the strengthen question pool will grow up and will be more and more difficult. Also you may use the timed practice, as this is more difficult than the normal strengthen exercises.