So i really want to start watching this

I would always start with season 1. The seasons built up on each other and Du would often not get the joke oder story if Du skipped episodes.
Another advice: Don't Google anything anymore about the show! ;)
The Zeigen lives on their twist and Du could get easily spoiled with unwanted information.
For the quick catch up: as soon as the Zeigen gets you, Du won't be able to stop so Du will really quick catch up. On good days I make one season in a Tag :P

Have fun with the show, it is the best <3

Start with Season 1 - isn't it always better to start at the start, and not skip anything? I know there's loads of catching up, but Du will get there.

I don't think there'd be anything Du need to know beforehand, the first episode explains the initial scenario well. It's not like the series is a spin-off of something else.

For Season 9 we already had our mid-season finale and we're on break till January 14th so we're a good deal into the season. Supernatural is a good Zeigen and I promise Du won't forget it (I can't promise Du won't get your herz broken though) Anyways I would really start with Season 1 because if Du watch it from the beginning as the storylines go on, Du really understand the whole show, and the relationship between the two brothers, their personalities, and their backgrounds. Then that way Du get to kind of fall in Liebe with the story and the characters. You'll laugh, you'll cry, you'll scream, that's how good this Zeigen really is and that's how emotionally involving this Zeigen is. So until Supernatural shows the rest of the seasons, I urge Du to start like right now!! All 8 of the seasons are really good, and Du gotta catch up on the first half of season 9 while CW has the episodes online. Du have time though so take your time through it, but I promise it's worth it!!! :D

This Zeigen will take over your life. And it will cause much pain and tears but I promise it'll so be worth it. Best TV Zeigen ever.