The first issue is due to the bootloader not installed during the installation. You have to download Clover and install it on the boot drive.
Make sure that the EFI partition on the HDD/SSD is formatted to FAT32 and not FAT16!! It happened to me and I had to format the EFI partition again and then copy the content of the EFI partition from the USB drive on it.
The second issue is due to missing kext for your audio. I'm yet to figure out sound on my HP Probook. This can be sorted by Clover Configurator.
This app will let you to configure boot options and drivers.
edit: Just installed WoodooHDA kext and sounds is up..