HTX assumes that each hypertext document resides beneath a top-level directory and it recognises these document directories from their extension, which should always be ".htx". When it needs to locate the contents of a document, it will search inside document directories (to any required depth) looking for files with an extension of ".html" which contain the hypertext itself, in HTML format.
The first step in organising your hypertext documentation should therefore be to collect all the HTML files comprising each document together into a directory (or directory tree) and to give the (top level) directory a distinctive name such as:
The "design-study" part of this is the document name by which it
will be known to other authors, and the ".htx" part identifies it to
HTX as a candidate for the various operations it performs. Once you
have made a document available to other people, you should not
subsequently change its name, even if you move it somewhere else,
because other documents may be referring to it and will still know it
by its original name.
HTX Hypertext Cross-Reference Utilities