Why is the created partition not showing up when installing Ubuntu on VirtualBox?

Question

virtual box

I created a partition for Ubuntu with the required EXT4 file system:


Before that, during the installation steps, I only chose:
- language
- keyboard layout
- here the settings are


- if I choose the first one here, it will erase everything on the C drive along with my current OS (windows) ?


- I choose another option and then this picture:


Where is the markup menu? Why is the created partition with the EXT4 file system not displayed? What to do next?

What is meant by "all existing partitions will be destroyed"? That is, the only drive C on which windows is installed will be destroyed?

Answer 1

It was necessary to create a new partition and install into it at the step "Installation type"

Answer 2

Something I did not understand anything. Section EXT4 you create where? Apparently on your real SSD / HDD.
Ububntu is installed on VirtualBox. So what does your SSD / HDD have to do with it?
Judging by the screenshot of the Ubuntu installation, you put it on a virtual disk with a size of 10.7GB. At the same time, the created partition is 18.69Gb.