I completed the park bench tutorial, but the only thing was that I was not satisfied with the level of quality the finishing project was at. So I continued to work on it until I got to this.
For the bolts I used a noise modifier. Color #1 is grey and Color #2 is white.
For the wood planks, the modifier is wood. Color #1 is medium brown. Kinda light-ish. and Color #2 is light brown.
For the cement foundation, I used a speckle modifier. Color #1 is medium/light grey, and Color #2 is a very very light grey.