The easiest way to download and install the latest Apple OS X 10.9 Mavericks OS upgrade is to simply visit the Mac Appstore from your Mac and click upgrade, however if you want to perform a clean installation (format the old setup and install fresh) you will need to create a bootable removable disk drive as shown ahead.

We will be using a simple to use GUI application named DiskMaker X to build a bootable disk drive from Mac OS X installation application downloaded from Apple Macstore (or any other source). As soon as you launch DiskMaker X, the application automatically finds the OS X Install program and proposes to build a DVD or create a bootable install disk as instructed below.

Having the option to boot into an operating-system of your choice in multi-boot environment is an much needed feature. While PC's have BIOS options to change/select the booting order, Apple's Mac computers features an handy "Startup Manager" utility to enable boot selection during computer start, this comes specially handy when using Windows via BootCamp to pick which OS volume to boot.