Next, add more coins going around the middle coin...
... until you have one coin in the middle surrounded by 6 coins.
Next, start adding another layer of coins around the outside.
You did it!
What you end up with is a single coin in the middle surrounded by 2 layers of hexagons.
Hexagons fill space perfectly; that is, they tesselate.
What that means is as long as your supply of Coinstruction pieces and pennies doesn't run out, you can make this thing as big as you want.
This one has 8 layers of hexagons.
I didn't have enough pieces to make a 9th layer.