Though you don’t have to have 2 rods for carp fishing, it certainly does put the odds of catching a carp more in your favour. A good few carp anglers have a 3 rod setup, but its a bit too much to cope with if you are just starting out. So I would just stick with 2 rods for now.
For an average type of rod you will probably be looking at a 12 ft rod with a 2.5 to 3.5 test curve. If you are fishing big waters such as large lakes , big gravel pits and reservoirs then you will probably want to get a rod nearer the 3.5 test curve. This will allow you to use bigger leads and get better casting ability. Ensuring you can get it out as far as you need to.
If you are fishing smaller venues such as small lakes, commercial fisheries, canals and rivers, then a 2.5 test curve rod will suffice.
Nearly all the top makers of tackle make good rods for catching carp nowadays so it is really down to personal preference and budget. It is always worth going to your local tackle dealer and having a feel of the rods and a chat with the dealer. They are always more than happy to help people who are starting out fishing.