In theory multirotors aren't complicated; the only moving parts are the motors. In reality, there is far more to them. To build a drone from scratch requires at least a basic understanding of physics, maths and technology; and practical skills such as engineering, wiring and even coding. To then fly the things requires further skill and experience. Obviously the degree of knowledge and skill required increases with the sophistication of the UAV. Some multicopters come in plug 'n' play kit form, which means you side step a lot of the technical challenges. My aim here to is to help reduce the learning curve for you, by providing some useful tips that will keep you on track or at least save a headache.