See link for instructions.
When manually-editing a .sif file, make sure that tabs are used (e.g. GENE1
When adding a new ligand/receptor mediated pathway, you will need to update the following files at a minimum: networkXXX.sif - add the ligand (GENE1) and receptor (GENE2), as well as any downfield node that the latter controls (GENE3) GENE1 up-regulates GENE2 GENE2 up-regulates GENE3 receptorlist.txt - add receptor GENE2 ligandlist.yaml - add receptor/ligand pair GENE2: [GENE1]