Hope you are doing good.
Please follow the below steps to import Storm VM in Oracle Virtual Box:
(i) Click on New option after that a pop-up will come, give the name, type and Version. You can choose any name of your choice, after that select Linux from type category and other Linux (64 bit) from the version category:
(ii) Select the RAM size, you can allocate the RAM size according to your system RAM
(iii) Import Centos File and Select Ubuntu VMDK File as shown below:
(iv) Now Click on Create
Please try the above mentioned steps and let us know if you face any issue.
Feel free to revert if you need any further help