you have to print 4 pieces of this model. for this there must be either 2 times each one size or 4 times the same size.

setup: take the four parts and put them together like in the picture, now you can secure them with screw clamps or clamps and optionally use hot glue to stick them to the ground.

How to find the proper size: measure the part you want to mold and select the next larger shape. 
the file names tell you how big the parts are: H stands for height and W for width. the numbers are the centimeters. so the file name with H10_W15 is 10cm high and 15cm wide.

if you need another size let me know in the comments and i will make it available to you.