The bass clef, also known as the F-clef because it defines the line for the F note between two dots, is used for lower-pitched instruments such as the bassoon, the bass, and low brass instruments such as the trombone and tuba.
The piano part played by the left hand is also usually written with a bass clef. The notes played on the lines of the bass clef staff are, from bottom to top, G, B, D, F, A.
This order can be remembered with the aid of phrases such as Good Burritos Don't Fall Apart or Good Boys Do Fine Always.
The spaces between the lines, from bottom to top, correspond to the notes A, C, E, G.
The mnemonic device All Cows Eat Grass may help you remember the order of these notes.