Turning cards over to find matching pairs is traditionally read as the effort to connect past and present. Dream books link it to recollection and to noticing what belongs together.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.