That’s a nice question. Actually most of the newbies in Linux world don’t know that Live CD and alternate CD are two different things because of the way the install the operating system.
Live CD is generally provides graphical user interface (GUI) and hence you don’t have to enter any UNIX command to run the applications.
Alternate CD files are different and while installation you don’t generally get the graphical interface. While installation you will see Blue and gray screens which receives only keyboard inputs. Your mouse won’t work. (At least I have seen that way).
So in short, you need to download a separate Ubuntu file. Search for “alternate” in the file name and then burn it on a CD/DVD and follow the instructions above.
Hope this information helps you understand the difference between Live and Alternate CD.