Only a little bit. Once you've got your 3D printer set up and running, you have the option to use STL / GCode model files that you've either created yourself or downloaded online from sites like Thingiverse, MakerOnline, Printables, Thangs, and Cults3D (there are hundreds more!). Just be sure to check the licensing agreements and ensure it's for personal use only. Next, you'll need to use slicing software to scale your file, make any alterations you need, adjust settings such as flow rate, add or remove supports, and change the infill amount so that your printer knows exactly how to print this model. I know this might sound complicated at first but trust me, it's really simple, and if I can learn this stuff you can too! Having an understanding of 3D modelling is not essential but it can really help you to navigate slicers much easier, make tweaks to a model before you print, and start creating your own designs should you choose.