According to Wiki, the land on which the Georgia Guidestones were constructed was purchased in October of 1979. The monument was unveiled the following March. The structure is made of six pieces of granite, including a central pillar, four slabs surrounding the pillar, and a capstone contacting the tops of the other five stones. Each of the four slabs is inscribed with a set of ten guidelines in a different language on its two major faces, thus containing eight languages in all. The four edges of the capstone also each include an inscription in one of four ancient languages.
A few feet to the west of the monument is a large granite slab with its face set level to the ground, which Wiki calls an "explanatory tablet". The tablet contains information about the stones and identifies the languages used in their inscriptions. It also mentions a time capsule, but does not indicate when it was buried nor when it is to be opened.
From the east side of the monument, the guidelines in Swahili and Spanish appear on the upright slabs. The inscription on this edge of the capstone, I believe, is in ancient Greek. The "explanatory tablet" is seen in the background, through the openings between the stones.
This view from the west side shows the guidelines in Chinese and Arabic, and a capstone inscription in ancient Egyptian.
The guidelines in English are shown in this next photo. The hole in the central pillar points toward the celestial north pole.
A close-up of the notch in the central pillar.
Here's an oblique view of the "explanatory tablet".
This part of the tablet identifies the eight languages used to inscribe the guidelines, and their locations on the four vertical slabs. Besides the Greek and Egyptian mentioned above, Sanskrit and Sumerian are used on the capstone.
To learn more about the Georgia Guidestones, go here, here and here.