Apokolips, from a distance, appears to have an artificially smooth surface except for large crater-like openings filled with lava that emit long plumes of flame like a blast furnace. The surface has linear patterns on it like those of a printed circuit board and some of the lines appear to be canals with lava in them running to or from the craters.
At ground level there is an atmosphere of perpetual night-time, but we can still see that there are many skyscraper-like buildings set against a red sky. One of the buildings is said to be Darkseid's citadel and contains the war room of Steppenwolf which is protected by parademons and a large "demon dog".
Another residence of Darkseid contains his throne which is set high up on a structure like a Mayan pyramid while the whole building sits in a lake of lava.
Apokolips is usually said to exist outside of space and time, and travelling to and from it is done via a travel portal called a 'boomtube' which is a local technology. However, in this show, characters like Superman and Space Cabbie are seen to travel there quite normally. Also, the Justice League themselves make use of 'boomtubes' on occasions, and Batman is able to detect their use on Apokolips by using the scanners in the Watchtower.
There is another, similar planet called New Genesis which is only mentioned by name but which we know from elsewhere is a bright, 'good' compliment to dark Apokolips.
- Apokolips at Wikipedia.