The way to open a comic book showcase depends on its type. If it's a key-lock one, find the key. If it's a combination lock, enter the correct numbers. Also, make sure you're opening it smoothly to prevent any harm to the contents.
First, make sure you have the key or the correct combination. Then, gently turn the lock or handle to open it.
Well, to open a comic book showcase, you need to check if it's locked and have the appropriate unlocking method. Sometimes, it could be a simple latch, or a more complex lock system. Be careful not to force it open to avoid damaging the showcase or the comics inside.