You have to use certain bricks such as 8x16, 4x4, 2x2, and 1x1 bricks.
I pretty sure there is now eventing required but, in the server options there should be a sectiopn for that mod and it says at the bottom Color or something above a box eith the number 8 or something in it, I think thats the color.
8 is the default color but 8 is grey and 9 is brown (in the blockland default colorset)
The first color is 0.. So you subtract one.
Which would mean the first column is 0-7I see you two are very good in math.