Casting a Circle

I'm unsure of how to cast a circle can some one please answer these questions?
How do you cast a circle?
What do you need to cast a circle?
Do you have to be alone to cast a circle?
Do you need to cast a circle before each spell?

1. A circle is cast for three reasons. First it creates a sacred space between the worlds of the physical and the spiritual. Second it creates a protective shield around the area or person of work keeping unwanted things out or in depending on how you work it. Third it provides a way to store energy that is being built for release with an intended spell or work.

2. A circle is not required to preform magick however when doing ritual based spell work or what is refered to as high magick it is highly recommended.

3. Since a circle is used to connect the physical with the spiritual I like to use both physical representation as well as spiritual. The physical can be anything that connects to the caster. Rice laid on the ground in a circle, candles, stones ect. I personally use 12 stones that I chose from the world. Spiritually I use personal energy. This can be projected through a wand or through your finger.

4. Now to cast a circle I'll use my example.
1. Place your physical representation beginning in the north moving clockwise to the east then south then west and back to the north.
2. Then again around NE, SE, SW, NW.
3. Then the rest placed at will around your circle.
4. Next beginning in the North again using your dominant hand project energy out of your hand or finger and into your physical representation. Continue tracing a circle all the way around 3 times ending again in the North.
5. Finally select a code word or saying or prayer that you can use to activate your circle. When finished drawing your circle use your code to complete the process.

Thanks. That clears everything up for me.

How would one go about making a mobile or moving circle? I've been quite interested but never found any info on it.

The same concept just using a mobile reference. For instance if you have a small stone that you use as your physical piece cast your circle based on that stone. Then carry it with you. You can also discard the physical and cast a energy circle that travels with you anyway.