Good idea, water cooling is much better than air. However,
1/wrong section
2/reserve=reservoir
3/you start with a long piece of tubing and cut it into pieces of the right length, one per component
4/you've not said a budget or what you're cooling
Setting it up is plumbing the thing together, filling the reservoir with water making sure some has run down to the pump, then running the pump for a couple of seconds with the system off. Refill reservoir, repeat. When the system is pretty much full run the pump overnight with bits of kitchen paper near the blocks. If any are damp in the morning, sort out the leaks then retest.
Laing make good pumps. Very good pumps. EK make good water blocks, thermochill for the radiators. Reservoir, as long as it doesn't leak you're good. Tygon make excellent tubing. Bitspower make the best barbs. However if your budget isn't unlimited you'll probably have to compromise on some of these.
Answer can be more detailed if you specify budget, reason for using water, components to cool. Cheers