The 3d printing part is relatively easy once you have the speed and temp for the filament you are using given its specification needs. PLA and TPU are super easy to print.

If you want to print with minimal fuss you really need to learn how to model really well with either CAD, box modeling, or 3d sculpting software. Also, understand mechanical tolerances for functional pieces that have to work together. The saying "garbage in, garbage out" is really true with 3d print quality.