Connecting a turntable?

If you have a Phono input it will provide the additional amplification needed for the ceramic cartridge, and perhaps even more amplification for a magnetic cartridge, made available by a switch. It also has extra bass boost to counteract the lack of bass in the recording, done so as to keep the grooves from making use of lots of platter real estate. By minimizing the bass, the recording time is increased.

If you don't have a Phono input, but you have an aux input, you may have to crank the volume and the bass to get reasonable sound, because the phonograph cartridge doesn't produce much output as compared to "line-level" devices such as a line-out on a tape deck.