I have found a nice program on GitHub that reads data from “A” and puts it in a text file, it is released under GPL3.
I want to modify it to put the data in a database instead and then release it as GPL3. I’m aware of the bigger picture of the license but has never before actually done this by myself, therefor I ask if there are any particular pitfalls and mistakes that will go against the license that I shall look out for?
Do I have to fork it on GitHub or is it ok to download the code and incorporate it to my new software?
Do I have to make any attributions to the original author besides leave the original copyright claim at the top of each source file?
Shall add my own name as a contributor to the top of files I edit and what is the proposed form for this if so?
This might be quite trivial questions but I don’t seem to find a good guide describing these hands on part of building upon existing open source code.