As a student at Lund University, you get a personal access card. It costs nothing to get the card and doesn't take long. You can pick it up at the Study Centre, among other places.

LU access card (Lund University's website)

Student at the HBG campus

If you are a student at LTH in Helsingborg and need access to premises or computers at LTH in Lund, for example at the Study Centre, you can get this by contacting servicedesk@lu.se.