Handling Multiple Files in vim

Sometimes you need to edit multiple files in vim and use it more like IDE and not just a text editor. I explain here how best to do that.
My dotfiles: github.com/calinleafshade/dots
Twitter: / @calinleafshade
► Wallpaper credit zedotagger
www.deviantart.com/zedotagger...
► Music Credit: LAKEY INSPIRED
Track Name: "Blue Boi"
Music By: LAKEY INSPIRED @ / lakeyinspired
License for commercial use: Creative Commons Attribution 3.0 Unported "Share Alike" (CC BY-SA 3.0) License.
Music promoted by NCM goo.gl/fh3rEJ