There are a couple of ways to do it. Fasten it to the actual run with clips. There are specially designed insulator clips you can buy for fastening to wire. Or you can run short posts around the base. Either fiber glass or stakes even T posts.
Where I live it is especially dry and I do not irrigate. Therefore standard electric fence is mostly ineffectual... Cant get a good ground. So when I rebuild my coop I will be doing Bipolar fencing.... OR running a separate ground wire parallel to the charge wire.
Fortunately for me there is a product out there Designed specifically for Bad Grounding situations. And they do call it a Bipolar fence ... its a tape that has both the positive and negative wires woven right into it.
Good luck
deb