@FoggyFinder I think you made a few mistakes:
"Did you saw Dark from Netflix?" - Have you seen...
"I read Dark has parallel to Strangers Things, so decided to ask" - I've read that "Dark" (.....don't know about parallel...) .... so I (I - is important) decided to ask
"weird, I watched only 2 first" - I have watched
"I say when will have watched the first season" - I will say when I have watched/I will say when I watch (http://engblog.ru/present-perfect (сложные случаи употребления present perfect))