Is it true that before the first use, i need to charge the battery a few hours?

Yes. Charge the battery overnight before first use, unless the manufacturer recommends otherwise.

A FEW HOURS

TRY 16
When you get your new phone the batterys level of charge needs set.
If you charge the battery only a few hours at first then thats all it will ever accept.
Always charge the new battery overnight with NO interuptions for best use.
After a year or so let it go COMPLETELY dead and do this again as this will help your battery.

Usually you have to charge it atleast 16 hours before you first use it.

Remove the door to the battery holder. Plug the battery into the slot. Only then will the phone give you a dial tone and ring when someone calls you.