Your questions have many answers here - have you tried the search function?
1. Red Hat distributions like to have three partitions, but it is recommended that you have four. (Create a partition for your personal files and mount it at /home. This way, should anything go badly wrong, you can completely install the OS and all your stuff will be just where you left it.)
These are usually ext3 partitions, which should be quite good enough for you 40Gb IDE drive. The redhat installer - anaconda - will handle the details for you. You'll need the advanced settings to partition the drive the way you want.
2. The preferred linux utility for backups is "tar", the tape archiver. You decide on a backup strategy and run tar from a script as a "cron job". Though, backup to another HDD is frowned upon, especially if it is a seperate partition on the same drive. It dosn't save you should the drive break-down or if anything happens to the box. However, this is often done.
For details - use the search function and read around.