The overall process of planning, designing, and building a walk-in closet drawing is vastly different from that of a standalone wardrobe. You're constructing a square box configuration and fitting it into an insufficient space that is almost certainly not square, plum, or level. The more walls you add to your configuration, the more difficult it becomes. A single wall of built-ins is easier to install than an entire room. However, no matter how large your closet is or how many walls you include in your Walk-in closet drawing, there will always be difficulties when installing. If you start your project with that expectation, it will be easier to deal with.