The files in the sources directory are
used to rebuild the binary format files for
Textures.

The general procedure involves
1) Turning off Flash Mode

2) Opening the file to be "dumped" (converted to
a binary file using the \dump command)

3) Selecting the format to be dumped on top of
(For LaTeX, this means choose VirTeX)

4) Choosing typeset (command-t)

5) When the dialog box comes up, navigate to the
right place to save the format (in the upper-left
box, find your TeX formats folder and open it),
give it a name.

6) Quit and then restart Textures.

For more details see the Textures User Guide.