U-Boot build in Arria 10(custom board)


I am building Linux OS for the custom board using Altera Arria 10 SoC and took the reference from

The bitbake is successful and following files are created in deploy folder :

There are kenel ( .dtb files) and root fs ( tar .xz file) created.
For u-boot (u-boot-with-spl.sfp-arria10-v2019.07+gitAUTOINC+7e090b466c-2-arria10-socdk-v2019.07+gitAUTOINC+7e090b466c-2) file is created.
In order to make pin changes , DDR3 , UART connection at HPS side (according to custom board) , where do we need to make changes??
Also , how do we generate: uboot_w_dtb-mkpimage.bin ,which we can boot to SD Card and what is u-boot*.sfp file , what is the exact u-boot file extension?