First, you can find show information by going to
https://www.arba.net/showsSearch.php#showsearch
You can search by date and location to find something near-ish you. There is only 1 show within a thirty minute drive of me, the rest are 2+ hours. Depending on where you live, you may have nearby shows or you may have to drive to get there.
Sometimes the show catalog is available online, sometimes you need to call or email the show secretary (that info should be given in the link above when you search) to have one sent to you. The catalog will tell you the date, time, and location of the show. It also has information about show rules, vendors who will be there, judges, and more.
Like SoDak Thriver said, it's easier to just jump and learn as you go. Most show people are very friendly and willing to help you out. So, you will need to determine which of your rabbits you plan on showing. Dwarf Hotots are a marked breed, meaning they need specific markings (the eyeliner mostly) in order to be shown. In many areas they are not that common so you may or may not have much competition. Holland Lops are insanely popular almost everywhere. If you're unfamiliar with what the Standard calls for in either of your breeds, ask your fellow exhibitors. Like I said, most people are willing to help newbies out.
Once you decide which rabbits to show, be sure they each have an individual tattoo in the left ear. Submit your entry to the show secretary (usually by email). If you aren't sure what all to include, ask.
Then, gather your supplies. Some basic supplies you'll need is a leak-proof carrier for each rabbit, water/food bowls for each carrier (often smaller than what you have at home since there will be limited space), a folding chair for yourself, and basic grooming tools (nail clippers, brush, etc). If you are planning to sell rabbits, make sure you take the pedigrees for those rabbits.
Arrive at least 20 minutes early on the morning of the show. You will need to find the check in table and pay for your entry fee. After that, find a clear spot and set up your carriers and chairs. You'll wait for your breed to be called to a certain table. There, the judge will evaluate each rabbit and compare it to the breed standard.
That is the very basics to get you started. Once again, most people are very friendly and can help you out. The first show I attended I entered a rabbit. It's the best way to learn, I think. For your first show, I would suggest entering just a few rabbits of just one breed. Sometimes both of your breeds are called up to be judged at the same time and that makes it difficult.