I downloaded this tree model to study by myself.
But there is a black square around the leave and the flowers.
When I make the tree with the tutorial, there is only one image texture box(left yellow box) like the below picture. so adding transparent BSDF & Mix shader makes the leave clear.
the first picture that I download has three image texture boxes in node, so it seems that it needs another solution for them to be transparent. is there any way that I can make it transparent??!