Step 1: Download oracle 19c cient Software, ftp to the server and unzip.

unzip /path/to/file.zip -d temp_for_zip_extract

Step 2: Create Oracle User and Group

Log in as a root and execute:

# groupadd oinstall

# groupadd dba

# mkdir -p /home/aqadmin

# useradd -d /home/aqadmin -g oinstall -G dba aqadmin

# chown aqadmin:dba /home/aqadmin

# passwd aqadmin

New Password:

Re-enter new Password:

passwd: password successfully changed for aqadmin

Step 3: Download RPM's

curl -o oracle-database-preinstall-19c-1.0-2.el8.x86_64.rpm https://yum.oracle.com/repo/OracleLinux/OL8/appstream/x86_64/getPackage/oracle-database-preinstall-19c-1.0-2.el8.x86_64.rpm

Step 4: install RPM's

yum -y localinstall oracle-database-preinstall-19c-1.0-2.el8.x86_64.rpm

Step 5: Create /etc/oraInst.loc file with below entry. 

inventory_loc=/home/aqadmin/oraInventory

inst_group=oinstall

Step 6: Change permission on below file

chown -R aqadmin:dba /etc/oraInst.loc

Step 7:  Install oracle software in Silent mode

export CV_ASSUME_DISTID=OEL8.1

./runInstaller -silent -nowait -ignorePrereqFailure -waitForCompletion -force "ORACLE_HOME=/aqadmin/19c_client" "ORACLE_BASE=/aqadmin" "oracle.install.IsBuiltInAccount=true" "oracle.install.client.installType=Administrator"

Step 8: Validate Installation

export ORACLE_HOME=/aqadmin/19c_client

export PATH=$ORACLE_HOME/bin:$PATH

which sqlplus

sqlplus

Step 9: Create tnsnames.ora file

LISTENER = (ADDRESS = (PROTOCOL = TCP)(HOST = AQA1VMSITORA01)(PORT = 1521))

RWDB =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = AQA1VMSITORA01)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = RWDB)
    )
  )

tnsping rwdb