Firstly, you should install the library WEMOS_Matrix_LED.h. After this installation, try running some of the example code below, the first is just to display a dot moving. The second is to change the intensity of the light.

Draw dot:

#include <WEMOS_Matrix_LED.h>
 
MLED mled(5); //set intensity=5
 
void setup() {
  // put your setup code here, to run once:
 
  
}
 
void loop() {
 
  for(int y=0;y<8;y++)
  {
    for(int x=0;x<8;x++)
    {
        mled.dot(x,y); // draw dot
        mled.display();
        delay(200);
        mled.dot(x,y,0);//clear dot
        mled.display();
        delay(200);        
    }  
  }
 
}```
 
Change intensity:
```cpp
#include <WEMOS_Matrix_LED.h>
 
MLED mled(0); //set intensity=0
 
void setup() {
  Serial.begin(115200);
  for(int i=0; i<8; i++)
  {
    mled.disBuffer[i]=0xff;  //full screen
  }
  
  
}
 
void loop() {
 
  for(int i=0;i<8;i++){
    mled.intensity=i;//change intensity
    mled.display();
    delay(1000);
  }
}```