Once you’ve taken off, keep your knees bent, your arms loose and extended, your feet planted on the board, and your torso leaned forward to lower your center of gravity.
Avoid the tendency to adopt a squatty stance when learning. Balance is side-to-side, not front to back. You will notice that experienced surfers usually ride with their feet much closer together.
The proper stance includes focussing your eyes looking in the direction you are going.
Paddle around and get comfortable in the water. Find your “sweet spot” on your board, to take it into the water and paddle.
Your board should plane across the water, the nose slightly above the water. A good “go-to” balance position is having your toes touching the leash string.
If your nose is too high up, you’re too far back on the board. If it digs water, you’re too far forward. It is essential to find the sweet spot, as that is where you will achieve maximum paddling efficiency.
Paddle with long, deep strokes from as far forward to as far back as you can comfortably reach.
The best way to practice and prepare for hitting the beach is with another person nearby who knows more about surfing than you do, and can provide feedback and advice.
If you have a friend who surfs, ask for help. Pay an instructor. This is the most reliable way to learn the basics of surfing in a clear, methodical way. For a reasonable fee, he or she will teach you all you need to know and give you pointers that will help you get out into the surf and having fun quickly.