I have downloaded the package available on the project website.
What steps do I have to follow now?
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It only takes a minute to sign up.Sign up to join this community
There are plenty of installation guides on the website; I think you should take a look at those.
Besides, it looks like the package is available in the repository, so you can install it with
sudo apt-get install moodle
Take a look at this Step-by-step Installation Guide for Ubuntu. Still, if you insist on installing from source, their own documentation for Installing Moodle may help. Try those and comment/ask for help with any problems you encounter following the instructions.
Follow the instructions
26 is the Version Number, which you have downloaded and wish to Install. In my case, it has worked nicely.