ERROR! During RouterOs installation on VirtualBox - please help

Hi all,

I’m new to RouterOs and I am trying to install it on VirtualBox using some guides on internet. It should be pretty straight forward but I’m constantly getting an error during installation (screenshot in the attachment). If anyone can help and point me in right direction I would be extremely grateful!

p.s. I apologize in advance if the same topic exits somewhere on the forum, I have tried to use search to find some answers but came empty.

RouterOS use once installed near 30MByte, the disk you have created is only 4MB,
how you think to install it inside?