Don't build the whole thing at once. Go step by step. So, first plug the RAM and the CPU onto the MBD, connect the PSU and power it up. When you hear the cheerf

Don't build the whole thing at once. Go step by step. So, first plug the RAM and the CPU onto the MBD, connect the PSU and power it up. When you hear the cheerful "beep", then turn off the PSU and continue adding stuff. A PC builder's set of PWR/RST/LED cables is a must, as well as 4-pin SPKR, piezzo buzzer. Good luck!