Honestly, if you know so little about electrical wiring that you have to ask this, you probably shouldn't be doing it. However, I always approve of learning so here's the best FAQ I know of on the web for this subject. Because it's Tesla oriented some of the info won't apply, but much/most of it will.https://teslamotorsclub.com/tmc/threads ... q-a.12615/
I would add that the FAQ assumes that your 14-50 will be on a 50a circuit because the Tesla plug in EVSE assumes that. The LEAF EVSE only needs a 40a circuit. You can certainly use a 50a circuit, and I would recommend that if you're pulling new wire. However, if your panel is limited in capacity, you might have room for 40a, but not 50a.