Translated, this is basically the same as the Golden Rule “Do unto others as you would have them do unto you.” “An” is an antiquated english word for “if” (like in Shakespeare), so the Rede should properly be read as “If you harm none, do as you will.”
As a Wiccan, this Rede is the guiding principle that guides our every action. As you are living your life, you must ask yourself, “Am what I’m doing right now harming anyone or any thing?” If your answer is yes, you need to stop and evaluate.
We strive to live a life in harmony and peace with ourselves and the Earth, and doing any kind of damage, either physical, emotional, or spiritual is completely wrong. We seek to make every action an act of beauty and connection with Divine.
Obviously, this takes some work. We all get frustrated, and angry, and sad, and lonely. At such times, we need to try so much harder to feel that natural harmony with the Great Spirit. At such times we often use “tools” to help us reach that balance. These tools are prayer and ritual. In both prayer and ritual, you take special measures to help focus your concentation upon God or Goddess. You are deliberately focusing your attention on finding that connection. We need this connection to feel alive.