AffiLib can be used in order to increase reactivity and/ or specificity to a certain ligand or transition state analogue.
In order to use this option, make sure the ligand coordinates are specified in the protein structure- either in the self-uploaded PDB file or in the Protein Data Bank version of the structure. Important: Use this option for ligands consisting of at least 3 atoms, it does not support single atom ligands (e.g. ions). In case of important ions, consider fixing the protein residues in contact with it using the option essential amino acid residues.
Please provide both the residue number and the chain it is located on (can be other than the designed chain- the one you specified previous step).