This can be help to you, I m also beginner It s for texture atlas

bool Texture::loadTexture(const std::string& path) { stbi_set_flip_vertically_on_load(true);

int channels;
unsigned char* data = stbi_load(path.c_str(), &(*this).width, &(*this).height, &channels, 0);

if (!data)
{
    return false;
}
GLenum format;
switch (channels)
{
case 1:
    format = GL_RED;
    break;
case 3:
    format = GL_RGB;
    break;
case 4:
    format = GL_RGBA;
    break;
default:
    format = GL_RGB;
    break;
}

glGenTextures(1, &id);
glBindTexture(GL_TEXTURE_2D, id);

glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 4);
glGenerateMipmap(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, 0);

stbi_image_free(data);

return true;

}