If you intend to use sqlplus over a remote connection, see chapter Setting up the Oracle network name services, which gives a short introduction to the Oracle network name services, and see chapter Creating database user and schema which describes the connect identifier. The following passages will assume that you have local access to the database instance in your environment.
Note that the SQL scripts in this documentation are to be regarded as examples. The scripts from the current delivery packages may deviate slightly from the samples presented here.