It's made as a step-by-step instruction for installation and setup. This guide can save you months of work, and narrow it down to a few hours instead. It takes a lot of research, downloading and testing.
Which mods work together, which mods are lore-friendly, and which mods are 100% stable.
However, it's a very time consuming process to figure out which mods to use. The huge amount of fan-made mods & enhancements has made it possible to get pretty decent graphics and visual effects. With this guide, Fallout: New Vegas will become more immersive, have better graphics, and run perfectly well on newer systems. Not the 'friendliest' game engine to new computer systems, but fortunately this can be changed. Bethesda used the same game engine for Fallout: New Vegas, as they did for Fallout 3.
