I am a newbie to i.MX. Now, I am having an i.MX 6Quad SABRE board for Smart Device. I downloaded BSP L.4.9.88_2.0.0_MX6QDLSOLOX. In side it, I found the file: fsl-image-qt5-validation-imx-xwayland-imx6qpdlsolox.sdcard. The board now can boot from this image in SD card. Now, I want to build simple applications like GPIO, Timer, LCD.... running on this board. I found an application note: https://www.nxp.com/docs/en/application-note/AN3870.pdf
Is it a right document I should follow? What documents should I follow to develop applications for i.MX?