# Build tree to calculate beta diversity

I am trying to calculate beta diversity using the UniFrac distance on my data, each sample having OTUs values.

To calculate it, I saw it required building a tree with percentages that represented the OTUs. However, I was unable to figure what percentage fit each OTU to build the tree from the instructions I found on the internet.

For example, I saw in this link: http://readiab.org/book/0.1.1/3/1#4.1.2, that they build this tree:

Could you please explain to me how to build the tree?

FastTree.exe -gtr -nt < aligned_sequences.fasta > otus_tree.tre