There is a half inch space for the roads to be placed in-between the tiles The foam board needs to be cut to act as a base for the clay.
Start by finding the middle of your board. I find that drawing two diagonal lines from corner to corner is the easiest. Place one hex tile from the game centred on the board and trace around it.
Offset another hex a half inch from the orginal.
Draw straight lines out from the top and bottom of the hex.
Where those lines intersect with the others is where the corners of your next hex will be.
After you draw out that hex you will need to offset another half inch to form your next corners.
Continue until you have laid out your full board.
Add a 1-1/2 inch offset to the outside of your hexes to form the edge of your board.
Cut out all of the hexes and the main board from the foam board piece using an exacto knife.
I found that the foam board cuts easiest with a slow saw like motion. Just pulling it though leaves the foam very rough and holes where you don't want them. Be sure to cut the paper on both sides before trying to remove the pieces all the way.