Lithium jump starters store power in their lithium-ion battery packs. They are smaller in size, but they pack enough power to boost your car power source in case it is dead. They are much smaller and weigh way less than lead-acid jump starters and therefore much easier to handle.
When using those devices you only need to hook up the jump cables you get within the model itself and start the car engine after few seconds. All these lithium jump starters come with user manual and instructions which are pretty straightforward.