Newbie - HTTP POST / GET

public with sharing class HTTPPosting {
    HttpRequest req = new HttpRequest(); 
  //Set HTTPRequest Method
  req.setMethod('POST');
  //Set HTTPRequest header properties
  req.setHeader('content-type', 'application/json');
  req.setHeader('Content-Length','1024');
  req.setHeader('Accept','application/json');
  req.setTimeout(120000);
  req.setEndpoint('https://platform.modsolar.net/rest/createLead/{myAPIkeygoeshere}/');
  //Set the HTTPRequest body
  req.setBody('externalLeadId=ApptID__c&FName2__c=i360__Prospect_Name__c&Street__c=i360__Address__c&City__c=i360__City__c&State__c=i360__Prospect_State__c&Postal_Zip__c=i360__Zip__c&phone=i360__Prospect_Phone__c');
  Http http = new Http();
   try {
        //Execute web service call here
        HTTPResponse res = http.send(req);
        //Helpful debug messages
        System.debug(res.toString());
        System.debug('STATUS:'+res.getStatus());
        System.debug('STATUS_CODE:'+res.getStatusCode());
} catch(System.CalloutException e) {
//Exception handling goes here....
}
}