help in settings

Dear oscar thank you for this plugin
Oscar i need your help in plugin setting, i’m not developer and i can’t understand correctly what i must write in json fields

i putted this link in first field
http://freegeoip.net/api?ip={ip}
is correct or not?

but i don’t know what i must write in second field

but after add the group this error show to me

Warning: array_merge() [function.array-merge]: Argument #1 is not an array woocommerce-product-price-based-on-countries/includes/class-wppbc-settings.php on line 355

https://ww.wp.xz.cn/plugins/woocommerce-product-price-based-on-countries/