Sharing a slab is fairly simple. First, you select your slab portion you want to share.
Just left-click on the map and drag your mouse to draw a box on the grid. Once you have selected the area you want, let up on the mouse button and continue dragging to select vertically. You can also click on the small boxes on the sides of your selection to adjust the size. Left-click to complete your selection.
Now press Ctrl-C to “copy” the slab to your clipboard. You can now use Ctrl-V to paste it either in TaleSpire, or out in Notepad (for a backup) or into a site such as this one or TalesBazaar.