When you have your pieces sorted you only need certain ones and colors

Grey,brown,green,blue,and black

Your gonna need green slopes and tiles/plates with grey and black girders blue tiles and brown plates. With a bunch, of foliage such as grass leaves bushes plants, and trees. You can find a tutorial for trees on youtube oak or pine trees that will work fine. An oak tree could be an apple tree if you want you will also need a lot of blue tiles.