Version specific installation and update instructions are given by the Installation Notes section of the Release Notes for each version as found on the Wiki Download page (different from the sidebar Download link.) The FAQ also has installation instructions for the current release. This page gives an overview with links to the current release version. To install an earlier release, refer to the Release Notes for that version.
Note for 0.7
During the "Choose Components" section of the installation, there is an "Associate HTML with K-Meleon" option. Use this wisely; K-Meleon currently does not have an option to set itself as the default browser after this point.