Since there aren't any georeferenced points on the site, we're creating a local grid using a few close locations as references as I use a total station to do some measuring.

Aerial photographs can be used to establish the approximate coordinates of these locations, at least accurately enough for our purposes.

How can we use QGIS to convert our local coordinates into UTM or any other type of global coordinates in the easiest way possible?

CAD is presently being used to shift and modify the coordinate values, but that is not the most elegant or efficient approach.