I am trying to create 2 cubes, with one mirroring the other. Instead it appears to create one cube that is always connected to the center! This is my first attempt at creating a character using blender. I am finished with the body, and now I am trying to add hands. I put my cursor where I want the origin to be and then pressing Shift+A to create a cube, which I would hope would also create an identical cube mirrored across the center. Instead, it seems as though these two cubes always have to be connected in the center. Any suggestions? This is my first day using blender so forgive me for not knowing the terminology.
Shift A amd create a cube. move it to right along x axis beyond the center line. Make sure 3d cursor is at world origin by pressing shift + s and select cursor to world origin. With your cube still selected in object mode press F3 and search for set origin and select origin to 3d cursor. Select mirror modifier and make sure your axis is x going by your picture