WebGL2 Instanced Drawing indexed

how can I order matrices for texture atlas by using Instanced Drawing in the 2D games?

https://webgl2fundamentals.org/webgl/lessons/webgl-instanced-drawing.html

#version 300 es

uniform mat4 u_projection;
uniform mat4 u_camera;

in mat4 u_matrix;//<--Instanced Drawing
in mat3 u_atlas;//<-- need to index 

out vec2 v_texcoord;
    
const float xp[6] = float[](0.0, 0.0, 1.0, 1.0, 1.0, 0.0);
const float yp[6] = float[](0.0, 1.0, 0.0, 1.0, 0.0, 1.0);

void main() {
    float x = xp[gl_VertexID];
    float y = yp[gl_VertexID];

    gl_Position = u_projection * -u_camera * u_matrix * vec4(x,y,1,1);
    v_texcoord = vec3(u_atlas * vec3(x,y,1)).xy;
}

Forgive me for my bad English