I recommend you google this, I found some great videos that will show you how. Basically you need to mod the forks and adjust the rear shocks. (Alot of work! )
You best bet is to go and look for a lowering kit for you specific bike. Since I don't know what year and model your bike is I can't tell you where specifically to look. Try somewhere like Dennis Kirk. They should have kits the include all the link, coils and brackets you will need.
When talking about Harley Davidson you need to replace the shock absorbers with the smaller ones and the rear wheel should be replaced with a smaller one and the adjustment should be done perfectly. And now you can enjoy low riding on your Harley.