How do I put two Ubuntu OSes on the same hard drive?

Solution 1:

Assuming there is nothing you want to preserve on your hard drive, you can do the following:

1. When you install the first instance of Ubuntu, at some point during installation there will be a window called "Installation type". Choose "Something else".
2. On the next window you can erase and create partitions. Make sure you create at least two partitions large enough for Ubuntu installations.
3. Select the partition on which you want to install the first instance of Ubuntu and press Change. Select Ext4 under "Use as" and "/" under "Mount point".
4. Go ahead, finish the installation.
5. Boot from the installation USB again and repeat step 1.
6. No need to repartition, as that was done in step 2. already.
7. Select the second partition and repeat Step 3. for it.
8. Go ahead, and finish the installation of the second instance.

The next time you boot the computer Grub will allow you to boot to whichever instance you want.