Depends on your meadmaking technique, but the process is likely pretty similar. Apple juice, like honey, is low in assimilable nitrogen, so you'll want to add a nitrogen source (DAP, fermaid, generic nutrients, etc). It is high in sulphur containing compounds, which the yeast will use in lieu of nitrogen, so if your nutrient levels are too low, you'll know from the smell. The lower gravity of apple juice also means the yeast will be less stressed, so you won't need to age nearly as long to get a drinkable product. Also, I find a neutral ale yeast to be preferable to a wine yeast, like Nottingham or safale S-04.

Combine them! Make a ciser; they're fantastic and significantly higher ABV than traditional ciders.

Minimal. The only real difference is that the juice you make cider from is already at the right concentration to brew unless you're buying concentrates, so you won't have to worry about water treatment or anything like that. You already know how to measure gravity and calculate abv (or you don't care). Add-ins like hops or herbs work the same. You should be able to transition pretty seamlessly to ciders and even wines. It's beers that can be a bit more difficult and involved because they have a cook step.