The topic of nanotechnology and Nanomedicine is an interesting subject which is hard to understand by newbies. The published blogs and books are either pure speculation or they are containing lots of expert vocabularies. Instead of explaining what Nanotechnology is, the more interesting question is how to reduce the entry barrier to a level that anyone can understand it.
What i have learned from a first survey is, that nanotechnology means basically to build a 3d printer farm which is able to replicate itself. Some youtube videos about 3d printing farms are available. In most cases, it's a shelf of 4-8 printers who are working at the same time. If the printer was programmed to build parts for a new 3d printer, the setup is able to grow quickly. From the abstract perspective the printing farms asks for electricity, filament and and human worker and in exchange it produces physical objects.
In case of a molecular assembler the idea is to replace human work with robots, that means the 3d printing farm will become fully autonomously and doesn't need human intervention anymore. This allows, in theory, to build a structure similar to what the Star trek replicator is capable of.