I don't get this. I mean can anyone help me. im confused what are B2 and C1 and stuff like that. can any experienced duolingo doers tell me stuff like that? because the help button in duolingo doesn't really help much.
If this is what you are talking about, it's simply a way of grading language ability. I don't live in Europe, so I don't know too much about it, but I would assume some opportunities--education, employment--would depend on such certifications.
Common European Framework of References for Languages
This is the standard in Europe (and around the world) for language skills.
A1 - Beginner; around 500 words with 75 hours of learning
A2 - Advanced Beginner; 1000 - 1500 words with 225 hours of learning
B1 - Intermediate; 2000 words with 300 hours of learning
B2 - Advanced Intermediate; 2500 words with 400 hours of learning
C1 - Proficient; Can talk freely and fluently, however might make a few mistakes or not know words
C2 - Mastery
Don't think of aiming for C2 right away. Aim for A2, then B1, and so on.
Good luck on your German learning adventure!