If you have any interest at all in either Arc (stick), Mig or Tig welding you must visit the following web site.
The site gives you online access to a weld calculator which will give novices (and most experienced users) a better idea of settings (rod size, wire size, voltage, gas) for varying thicknesses/types of material for each weld type. This is an online lookup.
Better still there is a free online app. for those with smart phones (apple or android). You can do a lookup on your phone prior to starting work. From this site select the mobile app. option on the left.
Even if you are only thinking of having a play with welding, it will help you start in the right ball park rather than starting blind.
Keep in mind, the settings given are only a recommendation and not necessarily perfect for every application or individual.