The bass clef staff consists of five lines and four spaces. Each line and space represents a specific note, and together they cover a range of pitches that the lower-register instruments play.

Each of the lines and spaces indicate a note pitch ... Hence, a bass player would use the bass clef, as they play lower ...

You could use this mnemonic to remember the notes on the lines: You could use this mnemonic to remember the notes in the spaces ... too low you can switch to bass clef: ...