The Swift programs and tools are part of the High Energy Astrophysics Software (HEAsoft) package provided by HEASARC (NASA's High Energy Astrophysics Science Archive Research Center). Instructions for downloading Swift software are provided on the Swift Data Analysis Web page.
The software includes several packages, whose help files are provided below:
Individual tools for analyzing FITS data files:
A Quick FTOOLS Tutorial
Spectral Analysis:
The XSPEC User's Manual
Timing Analysis:
The XRONOS User's Manual
Specific Swift tools and data analysis:
Swift Software User's Guides (for each Swift instrument) are available from the Swift Data Analysis Web page.