English: You find your ID in the link of your profile page, e.g. https://www.linkedin.com/profile/view?id=%1s8539887%2s&trk=nav_responsive_tab_profile_pic
Dutch: Je vindt je ID in de link van je profielpagina, b.v. https://www.linkedin.com/profile/view?id=%1s8539887%2s&trk=nav_responsive_tab_profile_pic