stoped working after I took it apart.

ok so, my little sister came to me with *new * nintendo 3ds xl. the camera app kept crashing maker her hard reset by holding down the power button so i looked on this website and it said that it was the camera ribbon cabel. so i orderd one and i was going to go in and look around. after i put it all back togeather before i took it apart it worked perfectly apart from the camera problem but now it doesnt even turn on. the blue light comes on for ~4 seconds then turns back off, the orange light also turns on when i plug it into the charger but if i try turning it on it says the battery is low for the red light adn turn itslef off. im still experementing but im not sure what i did. so if any of you guys have an idea of what happened its much apreciated. i have about 1.25 years of electronic repair experience, but turns out thats dip diddly here lol. so yeah, if yall can help its really nice.