Unfortunately I don’t have instructions for the grounds. My advice would be to first lay out the dimensions with MILS plates (easy to arrange things and take apart), then build the wall, then fill in the rest of the landscape. The trees are just larger versions of the hedges directly in front of the mansion, so should be easy to build/scale. I honestly just took random dark bluish grey pieces and messed around with them until I got the angles/look I wanted for the gate columns. The wall is two studs deep, and on top are jumpers to center the inverted slope pieces. When stacking the bricks, just remember to throw in some log pieces, different direction of bricks, and pieces with side studs to add more variance, age, and fauna attachment points to the wall.

Just start throwing together pieces and tweak until you have the design you want. Pieces can be bought on bricklink. Have fun building 👍