Here is what you will need.
After cutting out your squares you need to fold them in half diagonally as shown below
Then you will need to fold inwards against the folds
The end result should look like the next picture,Crease well, I use my bone folder.
Then you need to fold down from the point inwards as shown
And do the same for both side, but only on one side, if that makes sense
This is the bottom layer of the Christmas tree, as I used the largest
square to show you, now do the same with the other three squares
And there you have your Christmas tree pieces, all you need to do now is put a little
blob of glue at the point of each part from the smallest and put one inside the other.
Here is the card I made using a tree.
I hope this is of some use to someone.
Thanks for stopping by x