Print some blank staff paper to write notes on (see Resources).
Learn the symbol that differentiates between the treble and bass clef. The base clef is represented by what looks like a large comma with two dots. (See the image for the actual symbol.)
Learn the mnemonic (memory) device for the bass clef notes. The bass clef has five lines and four spaces for notes. The notes on the lines starting from lowest to highest are G, B, D, F and A. You can remember this by assigning the phrase, "Good Boys Do Fine Always," to the notes. The notes in the spaces are A, C, E and G, or "All Cows Eat Grass." The mnemonic devices help you to learn the note names and order much quicker.
Practice the notes on an instrument. Using a keyboard can be easier at first because you can place stickers on the keys to remind you of which key is what note. Bass clef notes will be played below middle C, or the lower register of the instrument.
Start with a few notes at a time to learn the placement as it relates to your instrument.
Find some online games to help with the learning process (see Resources).
Find some music with bass clef and practice until you've learned to correctly read the notes.