Building a simple led circuit
If you don't need to control the LEDs individually, you can connect the LEDs in parallel, but you need a current-limiting resistor in series with each LED, like so:







simulate this circuit &ndash; Schematic created using CircuitLab

The resistor value can be calculated using Ohm's Law.  You will need to decide on a suitable current for the LED (NOT the Absolute Maximum value from the datasheet! - 10 mA is safe for common LEDs).  Determine the forward voltage drop of the LED, and subtrract that from the supply voltage to get the voltage across the resistor.