Assuming you have a common cathode RGB LED module, follow these steps:

Identify the Pins: Identify the pins on your module, which typically include a common cathode (shared ground) pin and three color pins for red (R), green (G), and blue (B).

Connections: Connect the common cathode pin to the ground (GND) of your power source. Connect the red (R) pin to a positive voltage source (VCC) through a current-limiting resistor (typically around 220-330 ohms) to control the intensity. Connect the green (G) pin to another positive voltage source (VCC) through a current-limiting resistor. Connect the blue (B) pin to yet another positive voltage source (VCC) through a current-limiting resistor.

Power Supply: Use a stable and appropriate voltage source (e.g., 5V) for your LED module. Ensure that the current is limited to prevent damaging the LEDs. You can use resistors as mentioned earlier for this purpose.

Control: To control the colors, you'll manually adjust the voltage levels applied to the R, G, and B pins. You can use variable resistors (potentiometers) or digital switches to do this.

Color Mixing: By varying the voltage levels applied to each pin, you can mix the colors to create different shades. For example, you can adjust the R and G voltages to create yellow.