How do I assemble this using the following circuit?
Physical Connections do not have to look exactly same as logical connections shown in logic diagram as long as they match "logically"

The LDR is a photon current source that changes its effective resistance from >1M in dark to &lt;&lt;10K in bright light. ( they often have a dynamic range of 3-4 decades max, where as a Panasonic 5mm Light sensor has a dynamic range of 4-5 decades and is faster and FET buffered. (also cheap)

The LDR has a large area and thus more current can be captured but also large C, so the RC equivalent response time depends on light intensity and equivalent R with a fixed internal C, As stated by @FakeMoustache this causes slow response at high R values ( or light pulse turn off ) 

Since the supply shown here is 6V and the Vbe threshold is 0.6V, a 10:1 voltage divider is needed to activate Q1 , thus  trimpot of 10k+ for R1 determines this divide ratio is my suggestion.

i.e. if R1 is 5K and LDR is 50K it is almost low enough to turn on LED. If R1 is too high then ambient ceiling light will trigger it without a colour filter.  Usually IR emitters and IR detectors work better and faster with high gain Op Amps with a black optical daylight filter. But for ambient daylight the LDR is fine or an unfiltered (optical) Silicon PD (photo diode) is fine, but since smaller, it needs higher gain OpAmp but also,is faster since low C due to small size.

Since this is your 1st DIY, try to experiment and watch for false triggers from ceiling lights, with high R1.or too low R1 with light source too far away.

If you want a better light sensor design look up the Panasonic Light sensor 5mm at Digkey