The arrangement of notes on The Staff depends on for what instrument the music has been written.  In the context of guitar, we often use the Treble clef, which is also known as the G clef. Music written on G clef and Grand clef can also be played on guitar but not the most usual method of writing  songs for guitar.

Treble clef looks like the following:

The notes on the treble lines are laid out as following:

A common mnemonics to remember the notes on Treble Lines is ‘Every Good Boy Does Fine’, and for the spaces just the word ‘FACE’.

We do not use bass clef or grand clef for guitar but on some music books, you may come across songs written using these clefs.

Bass clef looks like the following:

The notes on the bass lines are laid out as following:

Again, a common mnemonics for the bass lines is ‘Good Bikes Don’t Fall Apart’ and for the spaces ‘All Cows Eat Grass’

Finally, the grand clef, which is often used for instruments such as Piano, Organ etc. uses a combination of both treble and bass clefs together.  To join these two, we need a C note in between which is often refereed to as the middle C. The grand clef looks like the following:

There are couple of other Clefs such as the Alto Clef (often used for viola) and the Tenor Clef (used for cello) but not relevant to guitar.