Which server are you deploying it to. If you are deploying to Jboss Wildfly server, then you can create the user by running the following bat file.
This utility will ask for user name and password you want to create, And will generate the user. Use that user password to login.
JBPM-CONSOLE is configured to add users this way. JBPM-Console is depending on JAAS authentication, that means you can configure username and [passwords in a database also. Refer to Jboss JAAS documentation to configure a DB or LDAP for authenticaiton.