Please help us help you and fill where relevant:
Your LimeSurvey version: LimeSurvey Community Edition Version 6.5.16+240708
Own server or LimeSurvey hosting: own
==================
My university set up liemsurvey in a way that all questions are shown on one page, hence the reason I think, that the protection part is not shown when the survey starts. 
What can I do in this case? Any ideas? Thanks in advance.

What is the "protection part"?
a. Do you only display  a text or
b. Do the participants have to agree?

a. Display it at the start of the surveyin a "text display" question.

b.

1. Ask for consent in a list(radio) question at the start.
2. Create two surveys.
   In the first you ask for consent.
   If "Yes" link to the second survey by end-url.

Joffm

M.Magda wrote:

My university set up liemsurvey in a way that all questions are shown on one page

I doubt that. The display mode is a survey setting.

-  www.limesurvey.org/manual/General_settings/en#Format

You were right, I was just not using the right browser and now I have the option. Thank you for your answers!

M.Magda wrote:

You were right, I was just not using the right browser and now I have the option.

The browser should NOT prevent access to that setting. If you find that is the case, it is a serious bug. What browser were you using when you did not have access?