I have downloaded ubuntu 20.04 by following these steps. I tried running it on VirtualBox, but the screen is either just showing the desktop or, if I try to resize the window, it turns black and doesn't come back.
I tried re-installing it, changing the amount of memory it is allowed to use, and other suggestions I found from other questions, like this and this, on here, but nothing seems to work.
Some suggest that I run commands in the terminal in Ubuntu, but I can't do that when I don't see what's on the screen. I can't find the desktop icons or the sidebar menu. How can I fix this?