1. The Oracle Installer GUI is pretty straight forward and easy to use. You can create a sample database from there.
2. Make sure you have the appropriate permissions and that you have set the /etc/system parameters correctly. These are outlined in the Installation Guide.
3. With 8.1.7, I like to install from Disk instead of CD-ROM. Create a directory, say /tmp/oinstall and create two sub-directories; /tmp/oinstall/Disk1 and /tmp/oinstall/Disk2 (Case is VERY important). Then, install from /tmp/oinstall/Disk1/runInstaller.sh
Thank you. After the installation, the dafault database is created, if I want to create db with different structure, do I need to drop all the db files including control file, redo log and .dbf files? then I run the create db script to create the new database, and run the catalog.sql and catproc.sql?