RAS Maker 2 is a command-line extraction/compression utility written by Remedy for Max Payne 2. Presumably to save space, Remedy packed most of the game data into .ras files. These are extracted as needed while loading levels, etc. Obviously, as a modder, you need to get to these game data files, modify them, and then repack the data into ras files again. RAS Master is a Graphical User Interface (GUI) written by me over Remedy's RASMaker2 utility.
It should be pretty intuitive. You have three primary functions within the program; View, Unpack, and Create.
View: Without extracting any data, this will read the files and size of files within a given .ras file.
Unpack: This extracts the files within the ras file to a given directory. Although it's possible to just extract the data to the folder you have the .ras file in, I don't recommend it. It ends up creating a bunch of files and if you don't know what you're extracting to, it will be tough to repack it later.
Create: Use this to repack or create .ras files. This would probably be used in conjunction with the Unpack, so the file structure should remain the same. You may notice that I don't include the creation flags that RASMaker2 has. I was having some difficulty getting them to work properly (even from the command-line), so I'm using the flags necessary to create the .ras file and that's it. I may update future versions to include those flags.