Katpraline

Hi, I have 20 little pieces that I would like to print on a cardbord. Each has a specific place that's why they are in the same .stl file. Can someone tell me how to print each piece one after the other ( and not all in the same time)? I precise, I don't want to import each piece individually in cura as it will be impossible to put them in the right place and that you can only ungroup pieces from different .stl files. ( modify/ungroup objects). Do you know a way? Thanks in advance for your help.