Clef
Tenor clef notes
The five lines of the tenor clef are D, F, A, C and E, from the bottom up, and the four spaces are E, G, B and D. The tenor clef is the same C clef as the alto clef, moved up one line: here the fourth line is middle C.
Read it, then play it
Play the note you see on the staff. The exact key counts: how high the note sits tells you which octave.
The lines: D F A C E
From the bottom up, the lines are D, F, A, C and E. There is no standard rhyme; players learn middle C on the fourth line and count from there. Each line is a third above the one below it, so you are really skipping every other note name.
The spaces: E G B D
From the bottom up, the spaces are E, G, B and D. Read them from the lines around them: the space above middle C is D, the one below is B.
Read from landmarks, not note by note
Start from the note the clef marks: C on the fourth line. From there, every line or space up is the next note name and every one down is the note before. Middle C sits on the fourth line.
Above and below the staff
Notes that don't fit on the five lines get short ledger lines. With one ledger line either side, the tenor clef covers B2 to G4: 13 white keys on the piano.
How to read ledger lines