Zip file for the target includes four files: 1. ambiguous restraints; 2. dihedral angle restraints; 3. sequence file; 4. a README describing the sample and the nature of the restraints.
The guidelines on the NMR-assisted data can be found at: http://predictioncenter.org/casp13/doc/Montelione-CASP_NMR.pdf and http://predictioncenter.org/casp13/doc/NMR_format_descr.pdf