All you need to make your water pipe into a rig is a nail or banger! If you have a female jointed water pipe you need a male banger. If you have a male jointed water pipe you need a female banger. There are three different sizes to choose from so you will need to know the joint size. There are other attachments you can get for dabbing as well like a drop-down or reclaim catch. Those help to catch your reclaim instead of it going directly into your piece, which keeps your rig cleaner!
A drop down is a wonderful attachment for smaller dab rigs and water pipes. We highly recommend them even for rigs that are just for the flower. Having the bowl or banger further away makes the experience just a little better. If you do not want a drop-down, look at getting a slightly larger rig or water pipe.