Could you mention the website where the links are broken? This allows us to fix the pointers.
What design documents are you actually looking for? There are several algorithms and plug-ins that use Petri Nets. For some of these user manuals can be found here: https://svn.win.tue.nl/trac/prom/browser/Documentation
Please let me know if this is not what you are looking for.
I am looking for ProM design to learn how it translates processes into Petri Nets, what are algorithms, architecture details or say UML diagrams of software as well.
Also can you tell me tell me how can I check out trac svn repository for ProM 6?
Thank you for pointing this out, I will see how to fix this problem.
I think that you are mixing two things: ProM 6 is only a framework for (process mining) algorithms. Therefore ProM has the notion of packages which provide these algorithms. I think you're looking for these algorithms.
Searching for process mining, and more specifically process discovery, quickly turns up some often used algorithms such as the Alpha-algorithm and ILP miner. You might want to try this.
Searching this forum for checking out ProM should provide you with the hints and tips you need. In essence, you don't check out the framework but select an algorithm to check out and investigate.
Please let me know if you have any remaining questions.
For the other a search should return some results. Otherwise, look at the Publications webpage of Wil van der Aalst since he is most likely a (co) author of such papers.
I would still suggest to check out individual packages, e.g. the AlphaMiner package etc. since the framework does not contain the codes you are interested in. How to check out the code anonymously is mentioned here on the forum.