If you want to use the “Install Alongside Windows” option during installation with the destination to install Ubuntu on the HDD, you need to have enough unallocated space on that drive.
Right now the entire drive is taken up by a NTFS partition. Ubuntu cannot be installed to a NTFS partition.
To prepare for guided installation, you should delete the “Area51” partition or you can also format the whole HDD with a GPT partition scheme.
Don’t use Windows tools to prepare partitions for an Ubuntu installation. You can select the “Try Ubuntu” option from installation media to use a live session. From there you can use the “Disks” application to select your HDD and choose “Format Disk…”. Since your HDD has the same capacity as your SSD, make sure you have selected the correct drive before formatting.
After the drive is formatted, or if there is sufficient unpartitioned free space, you can start the installation and use the guided “Install Alongside Windows” option.
Make sure you have good backups before altering partitions or installing operating systems.