A charango is a small stringed instrument from South America that resembles a ukulele and is a member of the lute family. Authentic charangos were made with the back of the shell of armadillos. While there are other variations, the typical charango has 10 strings in five sets (called courses) of two. The traditional tuning of the charango is similar to a C-tuning on a ukulele. Here's how you can tune your charango properly.
Tune the first two strings (thinnest) to E unison. This means they should be the same octave. Use a pitch pipe or an electronic tuner to get the pitch if you can't do it by ear.
Tune the second set of two strings to concert pitch A, both strings in unison. This is a concert pitch 440 Hz on a pitch pipe or electronic tuner.
Both strings of the third set are tuned to E, but they should be one octave apart.
Tune the fourth set of two strings to C, both in unison.
Tune the thickest set of two strings to G, in unison. This G should match the G just above the middle C on a piano.
Use and electronic tuner if possible for best accuracy.