You can not just create indices but install downloaded indices or even access remote indices through network. First, you should set up Summa Server and create a test index using our Quick-Start guide

Local File Indices

Put downloaded directory with index files to data/bin/<index_name> folder and then do summa-cli 0.0.0.0:8082 attach-index <index_name> '{"file": {}}'

Remote File Indices

You may also attach any index available through HTTP: