First of all find some materials. It can be any natural material that you like the look of. Do be careful of anything that has thorns or sharp spikes
It can take a while to find all the things you might want to use for your work. So spend time walking round your garden or park deciding what might work well in the finished piece.
Once you've chosen your items you can break the twigs so they are smaller. Stack them in piles and move them around until you have what you want.
You can use as many materials or as few as you like. You can keep it really simple and just use leaves like the example below, where leaves have been gathered into a simple abstract shape on the grass.
Also look out for land art created by other things in your garden....
This line has been created by foxes, constantly walking in exactly the same place on the grass every night on their way in and out of the garden.