There are some very brief but adequate instructions here:
http://store.infiniteautomation.com/core
Mango is just a Java application, so the actual 'install' of Mango consists simply extracting files from a .zip file into a directory of your choosing. That's it!
What you are probably asking for is a step by step guide to installing Ubuntu and the Java JVM, which are both products NOT made by serotonin software, which is why you won't find an install guide! :-)
Otherwise Serotonin would have to make a million guides for every different possible system configuration that anyone might want.
I would suggest that if you need a step by step guide, try searching for these things:
*"How to install Ubuntu 13.10 server"
"How to install JDK6 on Ubuntu 13.10 server"
"How to unzip file in ubuntu"
"How to run .sh file on startup in ubuntu"
*
..Etc.
You could even make a note of the steps you follow and post them here to help others in future.