The main partition where the ubuntu system is installed is called root, and marked with /
This is the same like C: in windows.
Your personal files and settings are saved in your Home folder. That folder can be a folder in the / partition, but it can also be a partition on its own which is then marked as mount point /home. In that case it is independent from / and during reinstall you can keep it easily.
Like you said yourself, when having second data partition in windows, you can format C: and reinstall at any time, you still keep your files from D:. This is the same.

The swap partition is space temporarily used if the ram memory gets full. In windows you have a file called swap file, in linux you usually have a partition (although you can also have just a file).

From your Disk Management screenshot, you need to think first whether you want to shrink C:. Right now it is 200GB but if you plan to have common ntfs partition for data, I guess it's better to shrink C: and make the common partition as large as possible.

If you want to keep C: as 200GB that's still fine. The unallocated space is enough for installation of ubuntu.