Bdtyktl

I'm a complete beginner to Linux and Ubuntu, and I've been trying to follow a few tutorials to set up a Windows 10 and Ubuntu dual boot on my PC. I've tried a few so far, and this is the most recent

My PC is running 64-bit Windows 10, has an Intel i5-6600k, 8GB RAM, an Nvidia GTX 960, my motherboard is an MSI H110M Pro-VD, and I have a 1TB hard drive. I don't know if any of that will be relevant, but from looking at other people's posts about this, their issues seem to have something to do with their manufacturer.

When I was following the tutorial, my PC didn't seem to have an option for secure boot in either Windows or the BIOS, so I continued on assuming that it wasn't a feature of my PC. I should also add that I did spot an option for either "UEFI" or "LEGACY + UEFI", which I left set to "LEGACY + UEFI", as that was the default, and from what I've understood, everything should work with either option.

Whenever I try to install Ubuntu, the first problem I encountered was that Ubuntu can't detect Windows 10, so I have to select "something else", and manually set up the partitions. After that, I then ran into the problem that I could only add one more partition before my empty space became "unusable", and after looking into that, realised that my hard drive must some form of system where you can only have 4 partitions, and I had to make my linux partitions logical rather than primary.

First I tried setting up my partitions like this, where sda5, 6, and 7 are all logical. I then encountered the following error during the installation:

GRUB Installation Failed

The 'grub-efi-amd64-signed' package failed to install into /target/. Without the GRUB boot loader, the installed system will not boot.

So I looked for people with a similar problem, and I'm reaching the point where all the answers are beyond me - the only questions that seem to have answers are being asked by people with much more experience than I, so I'm having trouble understanding the solutions.

I've tried adding a '/boot/' partition, and setting the boot loader installation to go to there, but I still get the same problem, as that was just a last ditch attempt based off what it sounded like people were saying.

I can't figure out what I'm supposed to be doing, and it's driving me mad. I've considered running Ubuntu in a VM, but I don't see the point in it if I'm still going to have to start up Windows to use it anyway.

I hope I've provided enough information to figure out the problem, and I'd really appreciate any help I can get.