How to generate a request for obtaining coordinates in the Yandex Locator system?

Question

Computer networks

Understanding the yandex locator API
https://tech.yandex.ru/locator/doc/dg/api/geolocat...
Unable to get a working response from the service.
Here is my query:

I get invariably
<?xml version="1.0" encoding="utf-8"?>
Specify xml or json param Please
point me where am I wrong?
Here is the json:

{
"common":{
"version":"1.0",
"api_key":"My Key"
},
"gsm_cells":[
],
"wifi_networks":[
],
"ip":{
"address_v4":"178.247. 233.32"
}
}