A molecule can exist in either a staggered or eclipsed configuration. In the former, the bonds to a given carbon atom bisect the angles between the bonds to neighboring carbon atoms. Conversely, in the latter, the bonds to adjacent carbon atoms align with each other.
What informs the arrangement?
It is generally observed that the staggered arrangement is more stable due to a reduction in steric strain (caused by the overlap of electron clouds surrounding individual atoms). Specifically, the van der Waals strain (resulting from the overlapping electron clouds) is minimized when the atoms involved are smaller.
Therefore, the most stable or low-energy form of 2,3-dimethylbutane is the first Newman projection depicted below. Additional conformations of 2,2-dimethylbutane resulting from counterclockwise rotation of the C2-C3 bond by 60 degrees are displayed from left to right and top to bottom.