I've spent the last 48 hours trying to figure out how to install Lubuntu 21.10 as the guest OS in Virtualbox on my Windows 10 laptop. Unfortunately, as I was using the wizard, I had to close it then found out there is no way to return to it and no instructions aside from using the wizard, at least none that don't assume you're an expert.
Now I've gotten to the point where I am using the Lubuntu installer and I am stuck on the Partitions page. 
The blue drop-down has only that one option, 10 GB I set up earlier in the process. (Not dynamic if that matters.)
I know the Lubuntu OS doesn't know it's in a VM but I'm afraid to click Erase Disk. Can it erase my whole laptop?
I would choose Manual partitioning and I've partitioned my old computers before, but I want the whole 10GB for Lubuntu. I'm afraid to click it unless it's what I need to do because I may not be able to go back, especially after the mess I created before when I clicked out of the wizard.
On Lubuntu's help page I only see instructions if I were installing it to be the only OS on my computer.
What should I do here? I don't want to erase my Windows 10.
Add: I clicked the radio button for Erase Disk without clicking Next, and the screen changed to this: 
