Before you start your DIY:
Get to grips with the supporting wall
Make sure you know what material the wall is made of and the optimal type screw for that material.
What role does floor play?
Your wardrobe will be resting on the floor, which will need to be level to make a solid foundation. You need to consider the final floor surface: will it be carpet, tile or hardwood? How will it meet the wardrobe? Will the floor get a new finish after the wardrobe, or is it already standing on it?
And, similarly, the ceiling
If you install sliding doors, will they go right up to the ceiling? If so, do you have the correct measurements and possibly tools for that precision?