I don't understand what this is supposed to mean in English. Can someone please explain? It seems a very odd thing to say, and I don't understand the meaning.
People know you in this place (for example in your village) but they do not know you in other places.
The first example that came to mind is underage drinking. I picture one kid telling another kid to try getting a beer at a different bar because he's already recognized at this one... 'they don't know you anywhere else'.
Why do we need both nikde( anywhere ) AND jinde ( anywhere else) ?
You do not need both. The actual answer you tried matters.
For example, "Jinde tě neznají." is one of the answers we accept without "nikde".
Why is "Nikde tě neznají jinde" incorrect? Do 'nikde' and 'jinde' belong together as first position here?
They belong together. It doesn't matter in which position, but together.
Many thanks, that's clear!
Why "Tě nznaji nikde jinde" is not accepted?
The second position rule for "tě"
You cannot start the sentence with the word "Tě".
Nikde jinde tebe neznají. Why is that not accepted?
Use the short form tě in the second position.