@EntranceJew However, if your card is not in a secret set, you are gonna have to craft it. If you are planning to play F2P farm out the 200 gems from each solo campaign, complete any missions you can, disassemble any UR/SR that isn't going to be used, and focus on making only 1 deck.
@EntranceJew So, if you create or find a SR/UR from a secret set, you get access to that secret set for 24 hours. It helps with getting to be able to build archetypes a lot easier. If you run out of time, you can craft another UR/SR from that set and get access again for 24 more hours.