I basically used YouTube videos, forums (https://www.3dhubs.com/knowledge-base/how-design-snap-fit-jo...), and the instructions from the 3D printer's company. I have this one in my lab: https://www.flashforge.com/product-detail/4. I started with something very simple and only one filament. Then, did something more complex with two filaments. I have some videos here: https://randyfespinal.wixsite.com/randyespinalcabrera/3d-pri... If you are familiar with Fusion 360 or any CAD software, that helps a lot. I love fusion 360.