Ubuntu doesn't recognize hard disk XPS 15 L521X

I have a Dell XPS 15 L521X that was purchased in 2014.  It's currently running Windows 7, but I want to convert it to an Ubuntu 18.04 machine.  I downloaded the Ubuntu .iso and created a boot disc.  The installation of Ubuntu runs just fine until it's time for Ubuntu to find a boot disk.  No disks are recognized/found, so the installation can't continue. My laptop has a 32 GB mSATA SSD and a 750 GB SATA hard disk.  Do I need to wipe the disks first or do I need to make a change int he BIOS for Ubuntu to recognize the SATA drives?