"We are deciding" means you are literally going through the options right now, whereas "we decide" means more generally that you are normally the ones who get to choose, but you're not necessarily thinking about a particular choice at the moment. They are close, but not quite equivalent.
Yes. The direct translation is "we decide" but it can be used for saying "we are deciding" also. You might want to say "we decide" in the lessons just to be safe, though.
This lesson in "Present 1" is to help learners know the present tense of the verbs and the conjunctions.
Let's try to stick to that, ok?
I often find in the spoken Italian, that the voice is so fast that syllables get lost. I thought this was "noi diciamo" (we say), because I could not hear the "di" syllable at all.