A basic led circuit is nothing more than 3 simple things which are a battery, a current limiting resistor and an LED. A current limiting resistor is used to provide the accurate required current to the LED, connecting the LEDs direct with the battery or power supply will damage them or shorten their life.
Here are the four basic led circuits, in these circuits a single LED is operated with four different voltage batteries using a different current limiting resistor with each battery. If you want to operate your LED with other voltages like for example 4, 5, 7, 8, 14, etc. then you can also find a suitable resistor for these voltages with the help of LED led resistor calculator. There are many websites, which provide free led resistor calculator and you can find them by seach.