T103M is 120Volt timer that can handle all the Christmas lights.
Minimum on-off time 1 hour.
Rotate dial until current time lines up with silver pointer.
Set on-off trippers on dial.
Let's go step by step.
1) T103 has terminals A 1 2 3 4 >> terminals are also called poles
DPST (double pole single throw) and SPST (single pole single throw) are two different ways to wire this particular timer.
T103 timer can be wired numerous ways... but your project is not complicated.
DPST means timer turns off two terminals/poles (double pole) with each click/throw of timer switch (single throw)
SPST means timer turns off one terminal/pole (single pole) with each click/throw of timer switch (single throw)
2) T103 timer is ST single throw, all the lights come on at same time. So this timer is 1 channel.
1 channel timers are either ON or OFF and everything turns on-off at same time.
You cannot stagger on-off times with 1 channel timer.
If you want upstairs and downstairs lights to come ON at different times, you need two timers .. or a 2-channel timer (which is different ballgame).
3) T103 timer has 120Volt clock motor that is connected to terminals A and 1.
Look at timer and you can see small white wires connected to A and 1 terminals that power 125V clock motor.
When wiring this timer, your wires from 20 amp breaker box connect to terminals A and 1.
Black hot wire from breaker must connect to terminal 1
White neutral wire from neutral busbar must connect to terminal Ahttp://waterheatertimer.org/How-to-wire-T104-Intermatic-timer.html#T103http://waterheatertimer.org/B220C.html
4) Terminal 1 must be hot so when timer switch clicks ON, it sends power to terminal 2.
Your load wires connect to terminals A and 2
I made simple drawing of SPST option showing how to wire T103 to 3 receptacles.
Fixya downgrades image so it's hard to see.
Hot wire to terminal 1
Load wire to terminal 2
Neutrals on terminal A
To see image larger:http://waterheatertimer.org/images/110-600-21Kb.jpg
If you want to wire timer for DPST, which is necessary for loads exceeding 2 horsepower (1500 Watts) on each terminal
Notice black jumper wire from terminal 1 to terminal 3
Notice all white neutral wires to terminal A
To see image larger:http://waterheatertimer.org/images/110-600-17Kb.jpg
I made third image for guy who was wiring high amperage blowers, that show wiring for two T103 timers. Having two timers would let upstairs and downstairs lights come on at different times.http://waterheatertimer.org/images/110-with-2-timers.jpg