BestFit is a member of the DecisionTools Suite, a set of products for risk and decision analysis described in Appendix D: Using BestFit With Other DecisionTools. The default installation procedure of BestFit puts BestFit in a subdirectory of a main "DTOOLS" directory. This is quite similar to how Excel is often installed into a subdirectory of a "MSOFFICE" directory.
One subdirectory of the DTOOLS directory will be the BestFit directory (by default called BESTFIT4). This directory contains the BestFit program file (BESTFIT.EXE) plus example models and other files necessary for BestFit to run. Another subdirectory of DTOOLS is the SYSTEM directory which contains files which are needed by every program in the DecisionTools Suite, including common help files and program libraries.