Dan, there is a difference between defining the entire room and the "baseboard" for the layout. Since you mentioned "table size", I'll assume you mean the baseboard. Here's how to draw a simple horseshoe with 30" sides in a 12'x10' space:
-- Convert the 12'x10' measurements to 144"x120".
-- SCARM opens with a very small workspace. Zoom out so the top ruler shows more that 144 and the left ruler more that 120.
-- Open the toolbox.
---- menu/tools/toolbox or the little toolbox icon on the menu bar, 3rd from the right.
-- Click the little down arrow where it says "Start point" and select "Baseboard (abs coordinates)".
-- In each of the next steps, enter the first number in the "X" field and the second number in the "Y" field and then click the "+" button.
---- 0 : 0
---- 144 : 0
---- 144 : 120
---- 114 : 120
---- 114 : 30
---- 30 : 30
---- 30 :120
--- 0 : 120
-- You should now see a horseshoe without a line down the left side.
-- Click the "Done" button and to complete the horseshoe.
You can draw any shape you want, but the lines cannot cross each other. The simplest way for me is to draw the basic shape on paper and then write down the coordinates for each point. Unlike graph paper, SCARM places the X:Y coordinates in the upper left. Positive X values go from left to right (same as graph paper), but positive Y coordinates go "down" from top to bottom (the opposite of graph paper).
