You can disable secure boot in the bios by starting the computer and tapping the F2 key to enter the bios. You then can tab over to the boot screen. Please read the information below in reference to disabling secure boot in windows 10.
Thank you for that link. I was hoping it was something as simple as hitting a disable tab. This looks more complicated. Someone told me that some manufacturers have this. I was hoping DELL did have such a tab, to make it easier for their customer. I do appreciate the reply.