First Layer
Most problems that people have with a print can be traced back to the first layer. If you do not have a good foundation, whatever you build on it will have problems
This reddit has a wonderful WIKI that goes over many problems and how to fix them. https://www.reddit.com/r/3DPrinting/wiki/troubleshootingandcalibration/
For a print the file must include code to generate/use a mesh.