Just across the water in Zhuhai here. Used to have some friends doing electronics in HK Island apartments. If you are ruthless about space you can fit a lot in to no space at all. Vertical helps. For an example just look at any phone repair stall. Buy them a beer and chat to them about it. The basics are an oscilloscope, multimeter and soldering iron; a good bench PSU helps. Avoid the yesteryear learning method of storing and manually mounting components, instead order circuit boards with SMT components: far more relevant today and far more efficient in space, time and money terms.