Step 1: Go get stuff
(x1) OSRAM-brand photo transistor
(x1) NPN transistor
Step 2: Line up
Lay the phototransistor atop the NPN transistor such that the base of the NPN transistor aligns with the emitter (longer leg) of the phototransistor and the collector of the NPN transistor aligns with the collector of the phototransistor.