The document linked below is a pdf of a famous old book of clef exercises. Though it is written in French, you can use it just by reading the exercises themselves.
The idea is to practice reading note names (for our purposes, read English letter names, not solfege syllables). Pick a clef that you want to work on, and work through the exercises in order (if you already have some experience in a clef you can skip the easier ones). The exercises are numbered beside the staff, and each clef starts over at exercise 1.
For our purposes, if you can do exercise 15 at quarter-note equals 120, you have probably progressed far enough.
The book starts with treble clef, and then does bass clef and exercises on the grand staff (in which you practice alternating between treble and bass). There are then some archaic clefs that aren't needed for Harmony 1, but if you scroll through those you'll find exercises using alto and tenor.