These craters are only visible (at least with shadows that show depth) during a half moon. Each day makes previous craters less visible, but expose more craters and mountain ranges. A full day on the Moon is 28 days, the length of time it takes to revolve around the Earth once.
There is no dark side to the Moon. Since it is tidally locked to Earth (same side always facing Earth), the “dark side of the Moon” is in full sunlight whilst, to us, the Moon appears asa dark, nearly invisible disk. This is also known as a New Moon.