You wrote
(mistake, should be: Which floor were you on) Which floor you were on?
Correct
Which floor were (fixed) you on?
Questions: helper verb before the subject
3 mistakes
Em português basta mudar a entonação ('Quanto custa o tomate?'). No inglês, toda pergunta pede um auxiliar na frente do sujeito: 'How much do they cost?', 'When did you start?'.
To ask a question, put do/does/did (or is/are/was/were) before the subject: How much do the tomatoes cost? When did you start? Which floor were you on?
Pergunta = palavra de pergunta + auxiliar + sujeito + verbo.
Wrong: How much the tomatoes cost?
Right: How much do the tomatoes cost?
Wrong: When you started it?
Right: When did you start it?
Wrong: Which floor you were on?
Right: Which floor were you on?
(mistake, should be: Which floor were you on) Which floor you were on?
Which floor were (fixed) you on?
(mistake, should be: When did you start it) When you started it?
When (fixed) did you (fixed) start it?
(mistake, should be: How much do the tomatoes cost) How much the tomatoes cost?
How much (fixed) do the tomatoes cost?