What is Drop D tuning guitar lesson
In standard guitar tuning power chords (F5, G5, A5, etc.) should be taken with two or three fingers.
To get Drop D you should low sixth string on one tone (two frets). The string must give D note (same as the fourth string, but an octave lower).
Now you can take the power chords with one finger on three strings.
What is Drop D tuning guitar lesson (how to tune guitar to Drop D tutorial):
If guitar tuned on Drop D you can low all strings on one tone (two frets) to get Drop C. Many hard-rock and metal bands play in Drops (for example Metallica, Rammstein and many others).