Step missing in purr data build guide
In order to run the compilation in step 4, you first need to enter the purr-data folder by typing "cd purr-data". Consider adding another step in between step 3 and 4. 
In order to run the compilation in step 4, you first need to enter the purr-data folder by typing "cd purr-data". Consider adding another step in between step 3 and 4.