How to implement sorting using laravel and datatable?

Question

Laravel

Hello!
There are following tables:
Emails [id, email, user_id],
Users [id, user_name, branch_id],
Branches [id, branch_name],
Users is related to Emails as hasMany
Emails is related to Users as belongTo
Branches is related to Users as hasMany
Users is related to Branches as belongTo
The task is to implement a table with live search by fields: user_name, branch_name, email + sorting using Jquery datatable.
Code :
$model = User::with('emails')->with('branch');
$DataTables = new DataTables();
$data = $DataTables->eloquent($model)->addColumn('emails', function(User $user {
return $user->emails->map(function($email){
return $email->email;
})->implode(',');
})->addColumn('branch', function(User $user){
return $user->branch->branch_name;
})->toJson();
return $data;
This code did not solve the problem..
How to implement it on the server side?