"I do not know how to open this bottle."
Translation:Nevím, jak otevřít tuhle láhev.
Something like "Neumím otevřít tuhle láhev?" It is accepted.
Though there is a slight difference in meaning, I think. "Neumím otevřít" means sth like 'I don't possess the ability to open [the bottle].' It has a 'more permanent vibe.'
On the other hand, "Nevím, jak otevřít tuhle láhev." is something I'd imagine you to use when you have the bottle in hand and are confused about how to open it - you just don't know how to do it.