clue 1 - case letter
clue 2 - placement -no case letter or number
clue 3 - case letter
clue 4 - number
clue 5 - placement -no case letter or number
look, theres a pattern here.... the translated text says the letter or number is X (hypotetical), where X is always at the end of the phrase, EXCEPT when the clue talk about placements, when theres no case letter or number at the end of the prhase. now, the 6th clue.
clue 6 - Druhý znak je číslo 3. = The second character is the number of third; google translate mistaken the number 3 by the 3th position (not my fault, sorry), but after 5 solved prhases, 3 characters, you can use the pattern and ask yourself: "If this dumbass used numbers and letters in the end of phrase, but no when it's a placement, why should he do this now?"
You could be skeptical, but, why not try the TWO possibilities?
I think I made my point here, doesn't mattr if right or wrong.... I could try to draw something simple, but as I said before, I'm at workplace now, and can't be focused in you... this single message take some time, so, if I ansewr something else, it'll be near to monossilabic...
hope you get the concept now sonic...