Hello,

You have to first have to appear exam like GRE or TOFEL. You have to score a good enough mark which will say that you are good at english and you can have a good conversation aboard.

This is a 8 step process:-

1. Course evaluation(your domain)
2. GRE,TOFEl,IELTS
3. University selection
4. Contact professors
5. Transcript attest
6. letter of intent
7. target on A1 german
8. 1 page resume

you will get all the information from GRE webpage. They give all the details to students to get an admission aboard and they guide them too.

On the part of research, yes you have to do on any domain you are good at or anything you find interesting and you can do it.

Hope it helps!