There is only one way to be assured of proper scuba diving certification. You need to sign up with a scuba diving school that has its curriculum based on a recognized scuba diving training agency. These agencies will regulate and represent diving professionals and operators out there.
You have to go through this program for you to be referred to as a scuba diver. This gets you a scuba diving license. The license is what gets you a chance to scuba dive, as well as rent scuba equipment for your underwater excursions.
There are plenty of such diving certification agencies in the market. This means you need to know which among them you ahold sign up with. Look for ones that are closer to where you stay. They may have different approaches to the training, but their main aim remains the same. Some are internationally recognized and governed, while others make their programs in-house.
You shall start off with theory training, where you shall learn more about scuba diving safety techniques and basic scuba concepts. There shall be videos to get you to understand the idea better, as well as the safety practices. You will also be taught the scuba hand signals for underwater communication. This is also a great time to learn about the equipment you shall be used in practical lessons. You will read more on the relationship between depth and pressure, assembling and maintain your scuba equipment. Get to know also about PADI open water certification NJ.
You shall then process to a bit of water practical training under controlled circumstances. You shall be taught how to breathe underwater. You shall get you to know how to use your equipment, as well as how to float and surface while wearing the scuba equipment. There are a lot of skills you will learn at this stage, which shall take you several sessions to grasp fully. There shall be an exam at the end of this period. When you pass it, you shall proceed to train in a less controlled and more lifelike environment.
This real life section is where you shall have the skills learned from the previous section tested out. Your instructor shall look at how well you can dive, and refine your ability until you can dive as intended. You will be taught more about the actual diving conditions out there, and how best to cope with them. This also gives you an opportunity to check out the underwater scenery. You shall be tested at each turn until the instructor is confident in your diving skills. After this, you shall become a fully-fledged scuba diver, complete with a certificate to prove it. Check out for NJ scuba diving lessons.
More ideas here: https://www.britannica.com/topic/scuba-diving