Someday when I get really rich I am going to build my family a castle to live in. This is what my castle is going to look like. Follow this tutorial and you will be able to build your own castle.
Start up Blender.
Blender starts with a cube, light, and a camera. If
you can't see the camera and light zoom out by using the mouse wheel.
Press the X KEY to
delete the cube. Click Erase
selected Object(s). 
Press Spacebar > Add > Mesh >
Circle. 
Click OK next to 32
vertices. 
Turn Widget Mode off by clicking
the hand. 
Switch to Front View by clicking
View and then Front View.
Press the E KEY for Extrude.
Click Only Edges.
Hold the
Ctrl KEY and move up 6 units. A unit
is a square. You should end up with something like this picture.
This is a tower of the castle. 
Press the Z KEY.
This makes what you are working on see through. If you want to change
that press the Z KEY again. Here is what see through is like.
You are doing great! Go onto Page 2