First, it’s good to understand what algae is. Algae is a plant that grows with significant amounts of uneaten food and waste. Different types of algae can bloom. Some appear free-floating, others can seem scummy. They can also create filmy layers of the sides of your tank and on features in the environment. They can also appear grass or seaweed-like or be a dirt-brown colour.
Do not fret! No university degrees are necessary to be a successful aquarist. But even beginners to the hobby need to know the basics. They are vital to maintaining a healthy and trouble-free aquarium. PH, ammonia, general hardness, carbonate hardness(alkalinity), nitrite and nitrate levels— these are what you test for and keep an eye on. You do not want to send your dear fishes on a roller coaster ride of unstable water conditions.
Many varieties of aquatic plant are interchangeable in their ability to live emersed or submersed. But, when you decide on the look you are going for, do not change their environment too often. It will cause them stress, and they will likely die. When you know what you want, and change their environment to suit, it can take up to months for a plant to adapt. Patience is key.