65 BPM means 65 beats every minute: one beat every 0.92 seconds (923 ms), or 1.08 beats a second. In classical terms it is Larghetto, rather slow (60–65 BPM).
You often hear tempos around 65 BPM in slow ballads, soul and R&B slow jams, and slow blues. The metronome above is already set to 65 BPM in 4/4: press Start, and change the time signature, accents, subdivisions or sound if your song needs it.