A reference management software can help you with your scientific work:

• You can import references from catalogs and databases. This references can be systematicly archived and exported again.
• You can structure your sources
• It can help you with the knowledge organisation and with the creation of scientific texts.

The larger the literary part of your work (seminar thesis, bachelor's or master's thesis), the more valuable a reference management software is.

The Hochschule Geisenheim University licensed Citavi for its users.

There are two versions of Citavi:

Citavi Windows, the desktop version, which only runs on Windows computers, can be downloaded here.

You can access the browser-based version Citavi Web at https://citaviweb.citavi.com/start.

In both cases, you have to create an account first (pop-up window from Lumivero).
Log in with your HGU email address to receive the licence from Hochschule Geisenheim University.

Citavi is not the only reference management programme available. 
Especially if you are not writing your thesis in Word (or Word for Mac), you can use another reference management programme.
You can find an overview here, for example.