My Pc That I Just Built Won't Show Display on Monitor

[nuwin6]

I have recently finished my build and was excited to power it up for the first time. But it didn't boot. The monitor said no signal detected. I was using a HDMI 2.0 cord and all of the lights and fans on my pc were working. I have tried multiple things from checking all the power cables were firmly plugged in to changing the slot which my GPU was mounted. Some friends said I had to use a VGA cable to boot first and then I could use HDMI after downloading all the drivers. I won't be able to get a VGA cable for a little bit so can I have your thoughts on this. Thanks.

 

[drivinfast247]

Need specs of parts used for build.

 

[norcalsc]

Plug it in