This Preface explains a little about the TortoiseGit project, the community of people who work on it, and the licensing conditions for using it and distributing it.
The Chapter 1, Introduction explains what TortoiseGit is, what it does, where it comes from and the basics for installing it on your PC.
If you need a general introduction to version control with Git, then we recommend two videos on YouTube: Tech Talk: Linus Torvalds on git (about design and differences to other VCS) and Tech Talk: Git (more technical). You can also read Pro Git book (multiple translations as well as downloadable versions available) , user-manual man-page, or gittutorial(7) man-page which are a short introductions to the Git revision control system, explain the different approaches to version control, and how Git works (with a bunch of examples).
The Chapter 2, TortoiseGit Daily Use Guide is the most important section as it explains all the main features of TortoiseGit and how to use them. It takes the form of a tutorial, starting with checking out a working tree, modifying it, committing your changes, etc. It then progresses to more advanced topics.
The section on Appendix D, Automating TortoiseGit shows how the TortoiseGit GUI dialogs can be called from the command line. This is useful for scripting where you still need user interaction.
The git(1) man-page give git official document about command line client