Document-relative paths
Document-relative paths are
usually best for local links in most websites. They’re particularly
useful when the current document and the linked document are in the
same folder and are likely to remain together. You can also use
a document-relative path to link to a document in another folder
by specifying the path through the folder hierarchy from the current
document to the linked document.
The basic idea of document-relative paths is to omit the part
of the absolute path that is the same for both the current document
and the linked document, providing only the portion of the path
that differs.
For example, suppose you have a site with the following structure:

To link from contents.html to hours.html (both in the
same folder), use the relative path hours.html.
To link from contents.html to tips.html (in the resources
subfolder), use the relative path resources/tips.html. At each slash
(/), you move down one level in the folder hierarchy.
To link from contents.html to index.html (in the parent folder,
one level above contents.html), use the relative path ../index.html.
Two dots and a slash (../) moves you up one level in the folder
hierarchy.
To link from contents.html to catalog.html (in a different
subfolder of the parent folder), use the relative path ../products/catalog.html.
Here, ../ moves you up to the parent folder, and products/ moves
you down to the products subfolder.
When you move files as
a group—for example, when you move an entire folder, so that all
the files inside that folder retain the same relative paths to each
other—you don’t need to update document-relative links between those files.
However, when you move an individual file that contains document-relative
links, or an individual file targeted by a document-relative link,
you do need to update those links. (If you move or rename files
using the Files panel, Dreamweaver updates
all relevant links automatically.)