question

I'm not entirely sure about the context of your question, but you could start out by directly editing the item's custom data as a JSON string. You could set it to something like this:

{
  "data1": "test",
  "data2": "test",
  "data3": "test",
  "data4": "test",
  "data5": "test",
  "data6": "test",
  "data7": "test",
  "data8": "test",
  "data9": "test",
  "data10": "test"
}