How to create login/password for access to Confluent

I’m sorry, I’m newbie, I’m even not sure what exactly I need for my software - simple OSS Kafka or Confluent Cloud. Currently I try to install Confluent Cloud and see that access to http://myIp:9021/ is absolutely opened to anybody. To continue doing something (even to learning) I need firstly to close access for unauthorized user. How I can do it?