DELT is developed in PHP, by using the framework Yii and trying to follow the best practices, like MVC architectural pattern, use of ORM tools, RERO (release eary, release often), DRY (don't repeat yourself), etc.
It's still missing many things (most notably, comments in the source code and automated tests), and there is a list of ideas for further development.
If you want to install DELT on your host, you should first install Yii, and then download DELT or, even better, pull or fork the whole project from github.
If you are a developer and you know Yii, you can send patches or comments. One of the aim of the project is to use the sources to show students how to write a web-based application, by providing a sort of real-life example.
If you are not a developer, you can still help in improving the software. For instance, since Yii is fully internationalized, you could provide a version in your language of a file with all the user interface's texts, which would look more or less like this (in Italian).
In case of problems during installation and setup, just write a comment here or contact us through the form.