Select the item. Go to the Resize Objects button on the toolbar. Pick the last one which shows a resize within a dialog bubble. Now a dialog pops up which lets you define the height and width.
To color something, Shift right click to bring up the toolbox. Pick the paint brush. Click on the thing you want to change such as the border. It might now be the wrong color, so right click which brings up the color picker. Now select the color you actually want. If you want something to be transparent, pick the T at the upper right corner of the color dialog box.
