It sounds like you want to erase both hard drives before installing Ubuntu.
The most user-friendly way to do this is to use the "Disks" application from a live session to format each disk.
Boot from Ubuntu installation media and choose "Try Ubuntu".
Then launch the "Disks" application. Select the disk you want to format and click "Format". You should use the GPT partition scheme, when asked.
For the disk where you intend to install Ubuntu, that's it! When you install Ubuntu you can choose this disk as the destination and the installer will create the needed partitions and file systems.
For the disk you intend to use as a data partition, in Disks, choose the disk on the left and then click the +
button to create a partition. Pay attention to the description of the options for file systems and choose what is most appropriate for your use case. If the disk will only be used by Ubuntu, ext4
is a good option. If it will be used by Windows and Ubuntu, you might choose NTFS
, but keep in mind that this file system won't support POSIX ownership and permissions. FAT32
is a file system that is recognized by almost all operating systems but also doesn't support POSIX and cannot store files larger than 4GB. Also, FAT32
does not support partitions over 2TB, so this would be a poor choice for your 5TB disk, as you would need to create multiple partitions.
You can choose "Install Ubuntu" from the live session or you can reboot the installation media to install Ubuntu.