boot - Can't install Ubuntu on Lenovo Windows 10 laptop

I'm trying and failing to install Ubuntu on my Windows 10 Lenovo Thinkpad.

There's two hard drives, I'm trying to install Linux on the second (though either HDD would be great). I've an SSD (C:/) and a SATA drive (D:/), both working on Windows and both internal

The install Ubuntu process itself fails. Trying Ubuntu, it starts up OK. But when I open 'Install Ubuntu' from the desktop, that also fails. It pops up saying I don't have enough space. When I try and edit mount points it just fails with an internal error every time.

I ran Ubuntu boot-repair and the results are here: https://paste.ubuntu.com/26475540/

I took a photo of the messages that popped up before the "Try" or "install" Ubuntu boot menu:

failed to claim resource 1
nouveau failed to create kernel channel

I would really, really appreciate some help. I just want to say goodbye to Windows forever!

If possible, I would replace Windows entirely. I can't be confident Ubuntu will work yet though.

I've also attached a photo of my hard disk partitions on the Windows side - to prove there is unallocated space.

.

I ran commands as requested: 'sudo lsblk -f' and 'sudo lsblk -m'

ubuntu@ubuntu:~$ sudo lsblk -f
NAME   FSTYPE   LABEL UUID                                 MOUNTPOINT
loop0  squashfs                                            /rofs
sda                                                        
└─sda1 vfat     UUI   11E9-286A                            /cdrom
ubuntu@ubuntu:~$ sudo lsblk -m
NAME    SIZE OWNER GROUP MODE
loop0   1.4G root  disk  brw-rw----
sda    28.9G root  disk  brw-rw----

└─sda1 28.9G root  disk  brw-rw----
ubuntu@ubuntu:~$