Serial and parallel circuits and power
You can do it either way. Each LED can be its own loop, or you can do it in 

In series-parallel, you have multiple current loops.  Each loop can carry as many LEDs as you can power from your supply voltage. For example, if you had LEDs with a nominal 1.7Vf, then you would have 5 LEDs for a total of 8.5V. With a power supply voltage of 12V, a reasonable resistor choice for each branch would be (12 - 8.5)/.02 = 190. Closest standard 5% resistor value I can think of is 220 ohms which would give you 16mA per branch. Should be plenty bright enough.