@CodeKing Try installing the desktop first - https://retropie.org.uk/docs/FAQ/#where-did-the-desktop-go - and then selecting the boot to desktop - https://retropie.org.uk/docs/FAQ/#how-do-i-boot-to-the-desktop-or-kodi.
Make sure you're package list fully updated first - run sudo apt update from a terminal or use the RetroPie-Setup update function to update the OS/packages.