One aspect of the guitar is that certain notes can be played in different places on the fretboard. Often, it's down to the discretion of the player. On the music, the writer can put clues, such as Roman numerals, often with a 'B' or 'C'. But - that generally means play a barre at that fret. Not exactly what you need. Sometimes there can just be the Roman numeral to tell position.
Take the note made by open top E. That can be written on the top space of the treble clef, obviously. Now, when a player sees that note, he can play it top string open; second string 5th fret; third string 9th fret; fourth string 14th fret and so on. All the same note, but slight differences in tone, and one of them will fit with other notes around that same fret where the guitarist is playing on the neck.
For your example, it'll either be second string 5th fret, or third string 9th. That's how it is. You could indicate with a fingering reference - '1' would encourage 5th fret, whereas '4' would play 9th fret.
Apart from a note at the top of the piece, I don't think there's another way to indicate 'play from 5th fret'.