Hello to everyone!
I am trying to install Ubuntu onto a machine with an installed Win10. In the "Something Else" section I can't find my windows C: drive so that I can delete it and say goodbye and install Linux

Relevant specifications:
A. BIOS Legacy, not UEFI
B. 1 HDD which is Dynamic
C. 4 partitions (1. system, 2. custom with my data, 3. and another custom one with my data which is for some reason split into 2 with the same letter in the disk manager, but not in the My PC window = 4 in total)
D. The pen drive was formatted with a BIOS target.

What I already know using google:
I. I can't use a dynamic Drive. I need a basic HDD. But how is it possible if I only have one HDD with Windows on it? How do I convert it if it needs to be empty, yet I need windows to do the conversion?
II. My system can only handle 4 partitions at a time, so I guess I can't create one, which I understand, but at the same time why would I not be able to delete one and create one? (4 - 1 + 1 = 4)

What I want to know:
1. How do I make my pc just simply install Linux without windows? I am currently scooping my data 250GB to another PC with a "teaspoon" 8GB flash drive, so keeping the data is not a concern. In a day or so...

1.1 Is it going to be enough if I just simply choose the option "Erase disk and Install" instead of "Something Else"? How will Linux handle the partitions? Will the hidden windows partition be visible for the Linux in this case, so it can wipe it away? How it will handle the partitioning? Create one big partition? Ideally, I would want to have 100gigs for the system and the rest for myself. I guess I can do this afterwards?
2. Or should I do something before doing Erase disk and Install? Some disk management on the windows I have still currently running? Wipe all except windows and do something with that?
Thanks for reading and trying to help!