You can put this solution on YOUR website! It's not that easy drawing a tree diagram.
It's much easier with paper and pencil.
I've shown the complete tree for the first roll of a 1.
Then the second roll could be 1-6.
The sum is then also shown.
The complete tree diagram would also show similar trees for the second roll for 2-6.
I'll leave that for you to complete in addition to the sums.