Gabri
Yes, you can do it. But follow the steps as mentioned below.

1. Create all the questions (which you already did) as a survey project.


2. Navigate to the Data Analysis tab (Data & Analysis Basic Overview (qualtrics.com)) and click on export responses (Exporting Response Data (qualtrics.com))


3. Once exported you will receive a excel file, paste all the responses from your csv in appropriate columns in the excel exported.


4. Once you're satisfied with all the columns save the file as csv-UTF8 navigate to data analysis and click on import responses. (Import Responses (qualtrics.com)) (Note: the record date and response type will be ignored as they will be date of import and Imported respectively)

Hello Deepak and thank you for your answer, still something is not working.
So i've been to data analysis tab and i downloaded all the question (in xlsx right?) then I added the new answers (just one row to try out) and I saved in csv-UTF8.
but when i'm trying to upload it again i get "There was a problem reading your import settings from your computer. Check that the file exists and that you have permission to read it."
If i download the question file from the analysis tab in csv how many empty field to I have to leave in a row before getting my first question? (I counted 17 commas)

Gabri
There has been a case where the file import was blocked by an organization firewall. Please check if that's the case on your end.
If not, try deleting all the empty columns and check if the csv is getting created correctly. You should also check to be sure the delimiter or enclosure is not found in your question text [no " double or single ' quotes]. Sometimes you need to use the pipe | to be sure delimiters are not causing grief. 
Some other sources which might help in troubleshooting:
CSV Issues — Qualtrics Community
CSV & TSV Upload Issues (qualtrics.com)
Hope this helps!

Thank you for your help. I have no firewall blocking I'll check for empty columns.
But it's ok to export the questions in XLSX and save them in csv utf8? Or I should download the csv? If this is the case how do I bypass all the first empty rows? Adding commas before the questions? I'm trying to find a template or a tutorial whit no luck for the moment. I'll check your suggestions.

Gabri
You can download it in CSV as well and make the necessary changes.
There isn't a video available for now but you can look at this support page(Import Responses (qualtrics.com)). But kindly use the 3 rows header which you received within the csv file that was exported to your system. Populate the answers from your original csv(previous system) into this new csv (qualtrics) desired columns and then import it.
There isn't a need to bypass the empty columns, that's just a troubleshooting step.
Hope this helps!