Lots of beginners feel confused about ground, because it means different things in different situations. Let us explain it to you in simple words. Actually, all the points in the circuit diagram that has the ground symbol – they are connected to each other.
If it is a circuit with only a positive and a negative power terminal (like a battery), the ground is connected to the negative terminal. If it is a circuit with a positive, a neutral, and a negative terminal, the ground is connected to the neutral terminal. No need to connect anything into the ground, unless you are working with high-power circuits and/or something else is specified. So, the ground symbol is basically a way to simplify the schematics. When you design a circuit board, you sometimes want to create a ground plane. This can be to simplify the circuit design or to reduce noise in a circuit.