A product this good deserves an image this large.
Lube the chain every week, every time it is ridden in the rain, or every 250 miles. Which ever comes first.
The easiest way is to use a rear stand to assist. Put the bike in neutral and spray on lube as you slowly expose new chain by turning the rear wheel.
The cheap way involves finding a bit of flat ground and rolling your bike forward or backward to expose more chain.
Less lube more often = best.