OpenGL4.5 -绑定多个纹理和采样器

I'm trying to understand Textures, Texture Units and Samplers in OpenGL 4.5. I'm attaching a picture of what I'm trying to figure out. I think in my example everything is correct, but I am not so sure about the 1D Sampler on the right side with the question mark.I'm trying to understand Textures, Texture U