Download the software after buying a new laptop

Hello,

I apologize in advance for my English, because I'm from Germany and do not know if my grammar is fine. :)

I have the following problem ... I've been using for some time Catia for students, Release 21. The installation was successful and I was able to work very well, however I have now bought a new laptop and on the old device, the program is no longer available. Now I want to install Catia on my new laptop. But unfortunately I do not know how I do it. Can someone help me?

About a speedy response, I would be very happy.

Thx Oli