What model did you get? Does it have rechargeable batteries? Please read about
Rechargable Batteries if you're not familiar with safety aspects, charging, the counterfeit problem, etc.
IMO it's insane for these suppliers to send out PV's with zero instructions or warnings.
Lithium batteries can and have exploded. I'm not saying they can't be used safely. I'm
strongly recommending that everyone educate themselves about their specific device, use ONLY the batteries recommended by the manufacturer, and be aware of the quality of the charger that you use.
For example, I've replaced my Trustfire chargers that came with my kit with Xtar chargers because testing shows the Xtar has a superior design.
Do not leave batteries charging unattended.
I don't do it all the time, but it's actually a good idea to check batteries after charging with a volt meter. Also, when you replace your battery, fire it the first time pointed away from your face.