Google sheets append

Questions
2

If “use:user” is an array then the only choice you currently have is a Function-Node. In that node you would have to iterates over the items in “use:user” and return for each of it a key: value pair of the data that should be appended.

So the data you return in the node would have to have this format:

return [
  // First array item of “use:user”
  {
    json: {
      nameOfFirstRow: "value to set in first row",
      nameOfSecondRow: "value to set in second row"
  },
  // Second array item of “use:user”
  {
    json: {
      nameOfFirstRow: "value to set in first row",
      nameOfSecondRow: "value to set in second row"
    }
  }
]

The above data would then append two rows to the Google Sheet.

I hope that helps. If not, simply post example data that gets currently output by your node and I can then create the Function-Node for you.