Cracking out a card is reasonably straightforward under ordinary circumstances. However, I’d be cautious with an already cracked case. Typical approach is to use a flat head screw driver and insert it into the gap in the corner. You’ll need to apply a reasonable amount of pressure to break the seal and then you can pry it open. Be careful of your hand and also not to slam it in full force. Have done this hundreds of times and probably messed up once or twice as well
