To fix “We couldn’t create a new partition or locate an existing one” trouble, give the following solutions a try:
From that point, you should be brought back at the initial setup screen. Choose “Repair” then go to the advanced tools and start the command line.
TypeLIST DISK and identify your SSD disk number (from 0 to n disks).
Type SELECT DISK whatever disk number you have.
Type CREATE PARTITION PRIMARY.
Type FORMAT FS=NTFS QUICK.
Type EXIT twice (one to get out of DiskPart, the other to exit the command line tool).
Perform the above for any other HDDs present, but don’t make any other drive active at the same time of course. Then reboot and start in the installation over again.