60 BPM means 60 beats every minute: one beat every 1 second (1000 ms), or 1 beat a second. In classical terms it is Larghetto, rather slow (60–65 BPM).
You often hear tempos around 60 BPM in slow ballads, soul and R&B slow jams, and slow blues. The metronome above is already set to 60 BPM in 4/4: press Start, and change the time signature, accents, subdivisions or sound if your song needs it.