"We are working."
Translation:हम काम कर रहे हैं।
हम काम करते हैं would be 'We work'. It's in the simple present tense and is conveying that we work (generally or habitually) but may not be working at this moment.
हम काम कर रहे हैं / 'We are working' is in the present continuous tense and is saying that we are currently working at this time.
Correct. The verb करना is often added to nouns and adjectives to make them into verbs.
काम करना = to do the work = to work
पसंद करना = to do the liking = to like
In conversational Hindi (and Hinglish), करना is also added to foreign (mostly English) verbs to make them fit into a Hindi sentence.
Eg: मैं अब ड्राइव कर रहा हूँ = I am driving now