In fact, from the beginning, the South had zero plans of conquest or territory; they simply wanted to form the CSA and be left alone.
not quite.

from very early on, Southern politicians wanted to drive on Washington DC, take it, and have DC become the new capital of the CSA. they also wanted to take Maryland, Missouri, as well as the Kansas/New Mexico territories. there was even an attempt to form a pro-CSA "Pacific Republic" comprising of California and Oregon, and when that failed (when later CSA-general AS Johnston rejected this attempt!) there was an attempt to get Southern California to secede from the US.

there were also Southern suggestions to take Central America, the bordering Mexican states, and Cuba (all suggestions that the South had wanted when they were in the Union, to balance the huge expansion of free states), but these goals were only going to be pursued after whupping the damyankees back home, of course...