curl --request POST \
  --url https://x8ki-letl-twmt.n7.xano.io/api:meta/workspace/{workspace_id}/table/{table_id}/index/btree \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "fields": [
    {
      "name": "name",
      "op": "desc"
    }
  ]
}
'

{
  "id": "<string>"
}