I am installing Drupal for the first time. The online installation guide instructs to install the contents of the Drupal folder (that you unzip locally) "into the web root folder on your server". I take that to mean that I cannot put the Drupal files onto a subdirectory. Is that right? Does this mean that the index of my web site must be the index of the Drupal system?
you can install drupal in sub-directory like: domain.com sub.domain.com domain.com/drupal etc... There is no restriction in installation folder.