Beagleone ai

Hi All
I have just started learning Embedded Linux. I ordered a Beaglebone ai and managed to bringup the os, Connect Keyboard, mouse to that. I ran a few linux commands on that. Now I want to know how to develop an embedded application, say for example Blinking an LED to start with. Can someone give me a quick guidance. I have Decent experience with Microcontrollers without OS. So, I have working understanding of all the peripherals like I2C, UART, LCD etc… I would like to do the same on OS environment as a first run.