How do you charge battery and open the back

take the battery out of the car and charge it with a battery charger,or take it to a parts house,they will charge it for free,if it will take a charge.when removing the cables,remove the negative first(black cable),then positive(red cable) last! when hooking back up,connect positive first,and negative last! don't hook it up backwards!!! copy and paste the link,watch video............. Chevy HHR Battery Replaced - YouTube www.youtube.com/watch?v=bfkV9UAvhN8