Ubuntu is not much different from other Linux installations, only the install panels look different.
You can add and remove programs (or "Apps"
if you belong to the FB generation
) later at any time. And you do not have to de-install and such, becasue yu do not live in the Windows DLL-hell here.
If you want to change the Linux kernel to a new version however, you have to re-install all – or is there a newish trick – anyone?
^ First radio button should be right, or use the LVM Logical volume one. Have no expericence with that yet.
You have physical volunmes, and you have partitions, and then you have so-called logical volumes.
All need space on your harddisk, of course. Installing a logical volume deos not screw with the physical partition though, and can easily be tweaked, or removed. Should not have influence on the native Win installation then.