Start your search on relevant job portals at an early stage. Search for topics such as ‘university internship’ and the respective specialisms that interest you, e.g. HR or marketing. Also look for junior positions that are not labelled as internships.
If you are already working, check whether your work could be recognised as an internship, e.g. by taking on new tasks. In the first semester, there is a kick-off event on the subject of internships, where you will receive further tips.
And perhaps you will find what you are looking for here?