Aircard 781s unite pro att hotspot

I bought this hot-spot online and they sent me a cheap Samsung charger with a tiny small wire that I'm not sure is what I need to charge it properly. What size charger do I need. I also did not get the boost charge cable. What exactly is this used for.  I don't use a PC if that helps you with ur answer. If it's important to use can you tell me exactly what I need to look for when looking to purchase it. Thank u for all ur help