How to create user for connect to database

ERROR :[FATAL] [DBT-05509] Failed to connect to the specified database (cdb21).   CAUSE: OS Authentication might be disabled for this database (cdb21).   ACTION: Specify a valid sysdba user name and password to connect to the database.

First step:

./runInstaller -silent -responseFile /scratch/app/user/product/21.0.0/dbhome_1/install/response/db_install.rsp \oracle.install.option=INSTALL_DB_SWONLY \UNIX_GROUP_NAME=oinstall \ORACLE_BASE=/scratch/app/user \INVENTORY_LOCATION=/scratch/app/oraInventory  \SELECTED_LANGUAGES=en \oracle.install.db.InstallEdition=EE \oracle.install.db.isCustomInstall=false \oracle.install.db.OSDBA_GROUP=oinstall \oracle.install.db.OSBACKUPDBA_GROUP=oinstall \oracle.install.db.OSDGDBA_GROUP=oinstall \oracle.install.db.OSKMDBA_GROUP=oinstall \oracle.install.db.OSRACDBA_GROUP=oinstall \SECURITY_UPDATES_VIA_MYORACLESUPPORT=false \DECLINE_SECURITY_UPDATES=true

Second step:

dbca -silent -createDatabase                     \-templateName General_Purpose.dbc                \-gdbname cdb21                                   \-sid cdb21                                       \-responseFile NO_VALUE                           \-characterSet AL32UTF8                           \-sysPassword Welcome1                            \-systemPassword Welcome1                         \-createAsContainerDatabase true                  \-numberOfPDBs 1                                  \-pdbName pdb21                                   \-pdbAdminPassword Welcome1                       \-databaseType MULTIPURPOSE                       \-memoryMgmtType auto_sga                         \-totalMemory 4096                                \-storageType FS                                  \-datafileDestination /scratch/oradata/           \-emConfiguration NONE                            \-ignorePreReqs