Here are some examples:

I am walking by the sign that says "stop". (In this context, it means I am walking past something).

We are working next to the other team in the room. (In this case, I am saying we are working near the other team that is located to the side of us).

The dog ran along the riverbank to chase the people in the boat. (In this one, the dog ran on the land parallel to the river).

As the others said, it depends on the context of the sentence. I hope that helps and is clear. I can provide other examples.

Pero Juanito , tienes que aprender las palabras en un contexto .... hay millones de ejemplos.

same thing. the word choice may be used differently depending on the formation of the sentence.