FMXInno Chronicles: Installer Source Code Index / Repository

[CrownRepack]

Hey guys, im not so familiar with the checking thing that some installers have, like for example in fitgirl repacks, she give the options to check if some of the files were installed properly, and there is another thing that checks the hash/sha1 or something like that, i don't really have any knowledge about that "checking" stuff, can anyone guide me about this and also how do i add this feature to the installer, im still using Vesta installer.

Also one more thing, i just need to know how to make .nfo files like all the scenes, what software of what do they use to create it. Thanks to all in advanced!