Basic cube notation
Cube moves are usually written with face letters. U means the upper face, D means the down face, L means left, R means right, F means front, and B means back. A plain letter usually means a clockwise turn of that face. A letter with an apostrophe means the opposite direction, and a 2 means turn that face twice.
Notation depends on how you hold the cube. If the front face changes in your hands, the same letter can refer to a different physical side. That is why solvers and tutorials often show orientation before giving moves.
Why solving is done in steps
A fully scrambled cube has too many pieces to solve comfortably all at once. Beginner methods reduce the problem. Instead of trying to fix every sticker, you solve a small target, preserve it, and move to the next target.
For a 3x3, a common beginner overview is: solve the first layer, solve the middle layer edges, orient the last layer, then move the final pieces into place. Different tutorials may use different names, but the staged idea is the same.
Beginner-friendly overview
Start by choosing a color for the first face and building a simple cross or first layer around it. Then place the first-layer corners so one side is complete. Next, solve the middle edges without breaking the first layer. The final layer usually needs a few short algorithms to turn and move the last pieces.
This overview is intentionally simple. A full tutorial would need diagrams and exact algorithms for each case. If you only need to solve the cube in front of you, the online solver can generate the exact moves from your current colors.
When to use the online solver
Use the solver when you are stuck, when a practice scramble becomes confusing, or when you suspect the cube might be invalid. The solver is also useful for checking your work: compare the generated moves with the step you expected from a beginner method.
If your goal is to learn, avoid only copying moves forever. After the cube is solved, review what changed during the last few steps. That observation builds intuition for future solves.