Version specific installation and update instructions are given by the Installation Notes in the Release Notes for that version. The Release Notes for the current release are linked to the Download page; the FAQ also has installation instructions for the current release. Thus this document only gives an overview.
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 doesn't have an option to set itself as the default browser after this point.