For Oracle 11g R2, there are some extras that should be installed because they aren't provided by default. But we'll get to those in a second, and a lot of them aren't fully necessary but they'll make it easier.
(Such as ssh!)

NOTE: All terminal commands can be copied and pasted however pasting in terminal requires the keystroke ctrl + shift + v, anywhere else ctrl + v can be used instead.

Now here are the files, separating into two parts and in .zip format. This is for x86. You should be able to open them without issue and if you don't there is an unzip utility on the site. The unzip utility download wouldn't load on my end so an alternate would be to open terminal using ctrl + alt + t, and enter the following commands.

sudo apt-get install unzip

Then:

unzip {file}

Of course replacing {File} with the .zip archive.

NOW you can follow the install instructions by Oracle linked here when installing the x86 version for the laptop.

Now when using the desktop and the x86_64 OS, you can find the installation files here applying the same unzip method as above. Honestly you shouldn't have a problem with the Ubuntu default, but again, Linux isn't always what it seems, so having a backup is always good.

Now for a quick an easy installation guide, this is x86.

The same installation guide is available for x86_64 found here.

The process isn't too long as long as you know your current computer specs, a lot of the instructions are mainly forced check if your system meets x requirment.

Enjoy!