It's very easy to use as a jump starter—just connect it (positive first), press the power button, then press and hold the boost button for 3 seconds. As my pictures show, mine was fully charged at 100%, and dropped to 86% after starting my vehicle.
You can also use it as a large power bank, which is great for road trips / camping. The LED light is super bright too.
It even comes with a car-style outlet, so you can power almost any device that needs it.
I'm keeping mine in the car, along with a tire repair kit and a portable air pump—better to be prepared and safe than sorry.
Friendly tip: don't forget to check and recharge it every 2.5 to 3 months to keep it in good condition, as recommended in the user manual.