The drawing "limits" as defined by AutoCAD is a rectangular area in which you are allowed to draw. This is the area which will be displayed when you "zoom" "all." It is also the area in which the visible grid and snap grid are extended to. They are preset by Autodesk as an area 12" wide and 9" high. This is too small to draw a large building in at full size, so you will need to change the limits to some reasonable number such as 300 feet wide and 200 feet high. You will do this in your prototype drawing, so you should never need to do it again, unless you are drawing a very large building. However, if you do need to increase the limits of the drawing for any reason and at any time (e.g., you are running out of room on the present drawing limits), pick "Format" then "Drawing Limits", then from keyboard, type coordinates of lower left corner: 0,0 <RET>, then type coordinates of upper right corner: 300',200'<RET> (note that this could be any number in feet or inches which will give you enough room to draw, enter X coordinate dimension with a single quote to indicate feet, then a comma, then Y coordinate dimension with a single quote to indicate feet). Note that if you want to indicate that your dimensions are in feet, use the foot symbol (the single quote key to the left of the "Enter" key on the keyboard) after your numbers, such as 10' ; otherwise, AutoCAD will assume inches for your units in setting limits. After setting the limits, type Z<RET>A<RET> This will zoom the drawing to the limits so you can see them.