The number of the folders, e.g. 4a, 4b,  indicates the compound number in the manuscript.  The name of the subfolders, e.g. 1H, 13C, indicates the revelant NMR file. 

Each indifidual file is directly generated and exported from Bruker NMR spectrometer. 

Subfolders could be imported, as a whole, to NMR softwares such as TopSpin or MestReNova, where could be fully resolved into corresponding NMR spectrum.