[Mashiro]

So it means if i want to install Ubuntu. I will have to wipe all my data and re-create all partitions? The fact of installing ubuntu into " C " Drive is still confusing me.

No, you don't have to wipe all your data, recreate all partitions and reinstall your OSs.

You shrink your Windows C: partition to make free space for an additional partition that will be used for Linux. That's all. During the installation of Linux you select this free space to create a partition for Linux.