无法使用PHP从JSON文件向MYSQL数据库添加数据

I'm new with PHP. I'v been struggling with this task for hours now. Earlier I used json_encode to get data from MYSQL to a JSON file. Now i try to revese and add the same data from JSON file to a new MYSQL database. I have a problem with converting the array to string before passing it to MYSQL database tho. The database works and I was able to add "players" there by inserting manual values instead of the $values from array. My code looks like this:I'm new with PHP. I'v been struggling with this