But in bitmain site it mentioned when LEDs are blinking it means that firmware is loaded , but next step it has written power on control board although it didn't mention when to turn it off does it mean that i should wait until control board itself turns off?
Yeah, you need to wait few minutes after blinking before you remove it from the power and taking the jumper back.
At least 5 to 8 blinking from the control board led before you remove it.
Look at this video here
https://www.youtube.com/watch?v=C-c5BJm4lbIor Try to change your SD card then repeat.
If it doesn't work there something wrong about the IP maybe it doesn't show because this miner detect the same IP as other miners you need to run the miner to the different router to check if it's IP issue or a software issue.