This review article introduces the design of the general purpose experiments ATLAS and CMS, which independently discovered the Higgs boson, showing how generic features are motivated by the characteristics needed to explore the physics landscape made accessible by the Large Hadron Collider accelerator, whose high collision rate creates an extremely challenging operating environment for instrumentation. Examples of the very different component designs chosen by the two experiment collaborations are highlighted, as an introduction to briefly describing techniques used in the construction of some of these elements and, subsequently, in the assembly of both detection systems in their respective underground caverns.