As a general rule, you are advised to install LibreOffice via the installation methods recommended by your particular Linux distribution (such as the Ubuntu Software Center, in the case of Ubuntu Linux). This is because it is usually the simplest way to obtain an installation that is optimally integrated into your system. Indeed, LibreOffice may already be installed by default with your Linux operating system. Detailed information is available on the wiki.
In short, you will be able to download LibreOffice packages tailored to your system's packaging standard (RPM or deb), or even get a .tar.gz archive for LibreOffice. You will then need to install these packages, first the main LibreOffice binaries, then the additional components such as language packs and built-in help.