If you focus on one project, it may take you not that long for a first proof of concept?
If you have chemical knowledge already, say you want to produce ethanol from glucose.
First you identify an efficient pathway from nature (out of the literature).
Glucose ----(Enzyme1)----> Pyruvate ----(Enzyme2)-----> Ethanal -----(Enzyme3) ----> Ethanol
Enzyme 1 already is in the organism. So you have to express Enzyme 2 and Enzyme 3 to make the organism produce ethanol.
Easiest way: Have these genes synthesized in a codon usage that your organism efficiently translates and insert the DNA into that organism.
Attention, if you are outside USA that may be illegal.