Hi, Magda,
In "Settings / Text elements" there is a field "End-URL".
Here you enter the address of your page (with "http(s)

/")
And in "Settings / Presentation" you can set the option:
Either the respondents sees a link on the "Thank You" page or he is redirected at once.
But something to consider:
Usually this is done at the beginning of the survey. Therefore there are all the options to include your privacy policy and get the sonsent. Without the respondent cannot proceed.
And you can include a link to your page in the footer of each question or only on the welcome page. It's up to you.
Imagine: The respondent submits his data, afterwards is redirected to your page - and doesn't want to give his consent.
What happens? Nothing. He answered the questionnaire, you got his data, though he didn't want that.
Best regards
Joffm
P.S. I talked about the privacy plolicy options. Well, you didn't tell us which LimeSurvey version you are using.
This feature was included in version 3.x