1. At the MrBayes > prompt, type execute primates.nex. This will bring the
data into the program. When you only give the data file name (primates.nex),
MrBayes assumes that the file is in the current directory. If this is not the case,
you have to use the full or relative path to your data file, for example execute
../taxa/primates.nex. If you are running your own data file for this tutorial,
beware that it may contain some MrBayes commands that can change the
behavior of the program; delete those commands or put them in square brackets
to follow this tutorial.