OK, my best advice to you is to change settings in the BIOS to Legacy or Mixed Mode (UEFI/Legacy) before installing but first things first.
1. Use Windows Disk Management to automatically shrink your C:\ Drive after running chkdsk and Defrag.
2. In the free space that remains, use Windows Disk Manager to create an Extended Partition.
3. Insert your Zorin disk and use GParted to create:
a. 512 Mb /boot partition formatted to Ext4 - this is where GRUB for Zorin should reside.
b. Make a 30720 Mib Primary partition after /boot and mark this as '/' also formatted to Ext4.
c. At end of extended partition, create a 'swap area' that equals the amount of physical RAM in your computer.
d. Of the space that is left create a '/home' partition formatted to Ext4
e. Install Zorin choosing the something else method but do so from live disk environment desktop - run the installer from there.
4. Reboot into Windows 10 and turn off hidden power options - these are the settings that you don't normally access that put the drive to sleep for faster boot times - with this enabled you will never get Zorin to boot. Also turn off fast boot in BIOS if it is there.
5. Go to NeoSmart (
https://neosmart.net/) and download the free version of EasyBCD - use this to modify your Win10 BCD boot loader in order to add Zorin as an option at boot time - check out my dual boot scenario with Windows 7 as to how this works:
https://vimeo.com/110085401and Matthew Moore's video here:
https://www.youtube.com/watch?v=xlTgaWs9BD0