Computer help. Bootable devices.

[airsoftkid]

So I just finally finished building my computer, but now I start it up and there is just like this little load like screen with this little spinning "/" thing. And it loads through that, then it says "Bootable disk is not received" and then, something about No bootable devices, and there is no way to load into the bios that I'm seeing.

Any ideas guys? Thanks.