uploading art portfolio through studielink, osiris

Hi, I am planning to apply to art universities in the Netherlands for the bachelor of design (Design Academy Eindhoven, AKIartez in Arnhem). I am preparing projects for my portfolio but I begun to stress about the technical side of the application.

Could someone explain more or less how does the platform (studielink, osiris) work?

Do I upload a presentation, pdfs, what is the form?

how many slides/ pdfs am i expected to upload, what is the minimum and the maximum?

How should I format it? (only sketches and photos or should there be a description to each project?)

I will be thankful for any information since these schools don't provide any technical cryteria (or I can't find them) for the portfolio and I am sooo confused.