The treble clef is the general clef used for upper-register notes in most printed music. However, some music is written using the alto clef. Whereas the first staff line in the treble clef is E, the first line in the alto clef is the F beneath middle C. The reason for using an alternative clef is that an alto part generally uses lower notes, and the different clef reduces the amount of ledger lines needed. The instrument that normally uses the alto clef is the viola. Other instruments that occasionally use this clef are the bassoon, English horn and trombone.
Read the first note as it is written in the treble clef. For purposes of an example, assume the note is on the first line of the staff, meaning it is an E above middle C.
Count up the staff seven positions; begin with the position of the note you're transposing. In this example, start with the line that E is on in the treble clef (the first line). Count each line and space as you're moving upward. This should bring you to the fourth line of the staff. This is where E is located on the alto clef, since the alto clef is seven steps lower than the treble clef.
Write the E note on the fourth line of the alto clef.
Continue this process for every note.
Try a shortcut to transpose. Starting with your treble clef note, drop the note by one whole step. Then add an octave and write the note down. For instance, dropping the E above middle C one whole step would make it a D above middle C. Raising it an octave would place it on the fourth line in the treble clef. This is the correct placement for the E above middle C in the alto clef.