i need help for a project in php and sql [closed]

I am a young web developer in formation.

Firstly, I have to apologize, I don’t have a perfect level of English, everything I know, I learned it by myself, I never had English at school. I’m French. There may be some errors, I searched for every error, but it is possible that there are still some

For my end’s year exam, I have to code a website. Mine will be on the theme of Yu-Gi-Oh! The users will be able to post publications, comment, like a forum, create 1 or more decks, and note and/or comment on other users’ decks. I have an API as a base from which I have managed to extract the data, and everything is displayed correctly, but I would like to be able to build a deck and I don’t managed “yet” to create a deck.

I had as original idea, building a deck, but later for storage, rather than storing the entire deck in the database, save the deck in a variable, and save the variable instead of the deck
I code in OOP with DAO in PHP. Thank you in advance for your help.