You can learn drumming by ear, but learning to read percussion sheet music will help you grow as a musician. Often, drumming requires you to play intricate rhythms on several drums at once. Percussion sheet music makes it easier for you to learn from other, more-experienced musicians and allows you to precisely write down the drum patterns that you use yourself.
Learn the meanings of the notes and rests. Sheet music divides notes by the amount of time they take. So a half note takes half as much time as a whole note, a quarter note takes half as much time as a half note and an eighth note takes half as much time as a quarter note. Rests work the same way. A half rest takes half as much time as a whole rest. Notes can go all the way to 32nd and even 64th notes, but generally don't go smaller than 16th notes.
Learn about time signatures and measures. A time signature is at the extreme left side of the staff. It tells you how many notes are in a measure. So if the time signature is 4/4, that means there are 4 quarter notes in every measure. A measure in 4/4 can have any combination of notes and rests adding up to that number. For example, it could have two half notes or a half note and two quarter notes or a full rest. Most rock music is in 2/4 or 4/4 time, while waltzes are in 3/4. A measure is the way notes are grouped in music. One measure of music looks like a group of notes and rests between two bar lines.
Learn about dotted notes and rests. If there is a dot next to a note, that note takes one and a half times as long as it would otherwise. For example, a dotted half note would last for three quarter notes instead of the normal two quarter notes.
Learn about accents. An accent is a small triangle under the note. It means you should hit the note harder than the surrounding notes.
Learn about drum music conventions. In drum sheet music, each drum is written on a different horizontal line of the music staff. Usually, if the music is just for bass, snare and hi-hat, the bass is written on the lowest line, the snare in the middle and the hi-hat on the top line. If the music involves more drums, there will almost always be a key telling you which drum is written on which line.