Pianos normally have pedals located under the keyboard that are operated by the performer's foot and effect the sound. There are typically two or three pedals. The right pedal is known as the damper pedal. When the damper pedal is depressed, a mechanism of felt dampers are raised allowing the sound of the piano strings to be sustained. This is the most frequently used pedal of the piano.
The letters "Ped" provide the directive for the performer to depress the damper pedal and the marking to indicate the release is a flowery looking asterisk symbol. These directives should be exactly under the beat or fraction of the beat where the damper pedal should be depressed or released. It should be noted that there is a half-pedal directive that instructs the performer to depress the damper pedal fully and then release half-way before depressing fully again or releasing.
In the sheet-music example below, the damper pedal should be depressed on the first beat of the first full measure and released immediately after beat two of the same measure. This is repeated in the next two measures.
See complete keyboard notations in the Appendix.