Hi Jenney,For the first question, these two solution are all good.
1. Take Snapshot::
With snapshots, you can save a particular state of a virtual machine for later use. At any later time, you can revert to that state, even though you may have changed the VM considerably since then. A snapshot of a virtual machine is thus similar to a machine in "saved" state, as described above, but there can be many of them, and these saved states are preserved.
2. Import VDISK::
You can also backup the VDISK(.vdi file) after complete virtual machine build, then import the vdisk to a new VM.
1. First copy your VDI file into VirtualBox's virtual hard disks repository, such as D:\VM or somewhere
2. Start VirtualBox and create a new virtual machine (according to the OS you expect to live on the VirtualBox image):
3. When you're asked for a hard disk image, select Use existing hard disk and click on the small icon on the right:
4. Which will brings you to the Virtual Media Manager. Click on Add and select the VDI file from step 1.
5. After leaving the Virtual Media Manager, you'll be back in your virtual machine wizard. Now you can select your new VDI as existing hard disk and finalize the creation process.
6. Back in the main window, you're now able to start your new virtual machine:
For the next question, I'll reply it in another post.....