How to use bluebird promise for specific scenario

I need to use bluebird promise for following scenario (already implemented in native promise using sequential approach), but confuse how to do it in bluebird.

data : 
  [
     {
         field1 : value1,
         field2 : [
             subfield1 : subvalue1,
             subfield2 : subvalue2 
         ]
         field3 : value3,
     },
     {
         field1 : value1,
         field2 : [
             subfield1 : subvalue1,
             subfield2 : subvalue2 
         ]
         field3 : value3,
     }
  ]

• So I first I need a promise based parallel loop for each block
• In each block I need to perform four parallel separate function ( they have their own logic like http/db )
• Then I need fifth function which need data comes from one of above four functions
• Then I need save function
• Then same logic repeat for next block
• finally resolve promise

Currently I tried similar to following

var bbPromise = require("bluebird");

db.connect(dsn).then(prepareData).then( (results) => {

}).catch( (err) => {
    console.log(err)

});


function prepareData(dbObject) {

    let recordsToInsert = [];
    let promises = [];
    request.forEach(function(row, idx) {

        let procesedRow = {
            // data build from row
        };

        promises.push( childFunction(procesedRow));

    });

    bbPromise.all( promises).then( (results) => {
        // resolve here ?
    })
}

function childFunction(data) {
   bbPromise.join( 
        firstFunction(data), 
        secondFunction(data), 
        thirdFunction(data),
        fourthFunction(data)
    )
    .then( (results) => {
        data.firstResults = results[0];

        data.secondResults = results[1];

        data.thirdResults = results[2];

        data.fourthResults = results[3];

        return data;

    }).then( fifthFunction )
    .then( (results) => {
        data.fifthResults = results; 
        return insertData(data);
    })
    .then( (results) => {
        bbPromise.resolve(results);
    });
}

Its working but final successful call (See resolve here ?) executed before any of actual operations.

via kuldeep.kamboj