Hello,
I'm a newbie regarding system administration so please be patient with me 
We have 3 HP ProLiant DL380p Generation8.
I've made a bootable USB with windows server 2016, attempting to install it locally, configuring the BIOS boot order to start with USB, confirmed the USB is enabled (legacy as well), rebooted and nothing happened, the USB was completely ignored.
I've tested the USB on a regular PC with configured BIOS and it worked just fine.
I assume there's a tool I'm supposed to add to the bootable USB or some driver on the server itself? Either way haven't found any info on that.
I must be missing something very obvious, however I've literally wasted over 24 work hours trying different configurations and browsing user manuals with no success, so any input would be greatly appreciated.
I've also attempted to connect the server to our network, however it didn't communicate with my dhcp at all. Even setting the IP manually with the correct subnet mask didn't help, and I still don't understand when will it start being accessable, since all it shows me when attempting a network boot is attempts to contact dhcp with no success over and over again.
My prefered method would be to install it with the USB, but if you have other suggestions I'm open to it.
If you require any further information please do ask.