The strings of a twelve-string guitar are arranged in six pairs and are tuned traditionally in unison or octave. Although strings are a "consumable" when played on the instrument, they can last longer if given proper attention from tuning to last rehearsal.
Instructions
Step 1
Remove the old strings from the guitar. You can, of course, spin all twelve pegs and remove the strings "according to the rules", but it's better to just loosen and have a bite with pliers. There is no need to protect them.
Step 2
Pull the first string, straight to the piano.
Step 3
Pull on the sixth string, tune to E.
Step 4
Then stretch and tune the second string ("B"), the fifth ("A"), the third ("G") and the fourth ("D").
Step 5
Stretch and tune the additional strings in the same order. The extra strings will be either in unison with the main strings, an octave higher or an octave lower. Let the guitar stand for a while.
Step 6
Check the tuning, pull up the moving strings, starting with the main ones and ending with the secondary ones.