RE: First RC plane
The charger provided with the plane is a balance charger with auto-cut-off.
It will not overcharge the battery if you leave the pack plugged in via the small white plug. It is what you should use.
You are not missing anything either. It is an RTF in that everything you NEED is provided. You can clip the leads to your car battery to recharge the plane.
As already stated a 12v DC power source of suitable amperage is a better idea. I typically find several suitable transformer/supplies in my box of unknown wall warts...
Check yours ( everyone has em! ). You already may have a suitable charger.
Make sure it reads at least 1000mA ( 1 am ) 12 to 14v DC with a positive center tip. Almost all wall warts have the necessary markings to decode this.
As indicated, that is NOT a good absolute beginner's plane and will likely last a few seconds if you attempt to fly it without help.
NONE of the control surfaces are set up correctly ( yes this is what RTF means! ) nor is the plane trimmed out for flight.
As a result novices are faces with not only learning how to fly, but with trimming and setup issues that they know nothing about.
The "Trainer" monikker is due to it being designed for people who are still new to RC. For someone who has already learned how to fly and land it may be a good "Trainer" airplane as they proceed to hone their skill.
For an absolute novice tackling their first flight... no.
I often see people arrive with Park Flyers and Foamies, and blame the plane when they crash it.
If it survives ( assuming I was not quick enough to stop them ) I fix things up for them, and they are amazed to see it actually flying after all of their troubles.
Unfortunately even when I try to give them an intro lesson, and tell them that they need further lessons, the planes end up in the trash after subsequent attempts.