An exercise for learning the notes on the fretboard:

Pick a note to locate (for example E) and set your metronome to 65.  Then proceed to locate that note on the 6th string in all positions with each click of the metronome. Proceed to the 5th string (without missing a beat), then the 4th string, the 3rd string, the 2nd, and finally the 1st, locating the note on each string.  Don’t forget the open string positions.

Try this with all 12 notes.  If 65 is too fast, then slow it down.  Once you are proficient at it, feel free to test yourself by speeding it up.  Those just starting out may need to reference a note chart, which will show you all the notes on the fretboard, such as: