I'll give you the link in PM but don't expect lightning speed transfer.
Once the file is downloaded, go in VMM/Virtual Machine/Create "arrow"/Import and select the OVA file.
After that, you can set the VM by choosing number of cpu, amount of ram, etc... Zorin OS is very light and can do things with only 1GB RAM but choose 2GB if you can. Then disk space, default to 10GB but your choice (I select VirtIO SCSI driver in options), Default VM network but I change to VirtIO model. In the next page, you can give USB access to peripherals if you want but I left Legacy bios and no other images mounted. That's it.