When all else fails ... Read the documentation (anonymous)
Documentation is like sex; even when it's bad, it's better than nothing (anonymous, Internet)
These two quotations are more or less consistent with the authors' view on documentation. I do not like to have to read documentation, but it is necessary and at times indispensable. Most of this reference manual should not be read ! It is a reference manual and as such, apart from some general considerations which are given in the first few sections, the remainder of the manual can be considered for reference only.
FIT2D should be very largely self-documenting. All graphical menus and forms contain a ? button and/or a HELP button. Clicking the ? button will produce a list of the available commands and a short one-line explanation of the command. The HELP button will produce interactively scrolled help text, describing the whole menu or form, and the options and choices that are available. Within the keyboard interface you can obtain an explanation of the required input for every prompt by entering a question mark (?). The ``HELP'' option is also available within many menus.
Nevertheless the Reference Manual exists, and I feel it can be useful. If you want to perform an operation but do not know the name of the command there is a large index to help you. If you want to know precise details on the workings of a command, the reference manual contains extra information and cites articles and books containing more information.