Learn Portuguese (Portugal): Nós vamos para baixo.

In English, "down" works as a direction by itself. In Portuguese, baixo refers to the location of being low or down. To show movement towards that place, you need the preposition para (to/towards). You are literally saying "We are going to down."

Can I leave out the word Nós and just say Vamos para baixo?

Yes, absolutely! In Portuguese, the verb ending tells you who is doing the action. Since vamos can only mean "we go" or "we are going", the word Nós (we) is optional and is usually dropped in everyday speech unless you want to add emphasis.

Does vamos mean "go" or "are going"?

It means both! Portuguese does not always use an "-ing" form the way English does. The simple present tense vamos (from the verb ir, meaning "to go") can translate to "we go" as a general habit, or "we are going" right now.

How do you pronounce the 'x' in baixo?

In Portuguese, the letter 'x' can make a few different sounds depending on the word. In baixo, it makes a "sh" sound, just like in the English word "shoe".