How to save data from TextInputEditTex of Android Studio in FirebaseDatabase?

In Firebase:

On Android:

content_user_home.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/content_user_home"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.didierzuniga.domix.view.UserHomeActivity"
tools:showIn="@layout/app_bar_user_home">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <android.support.design.widget.TextInputLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/EditTextGrey"
        android:layout_marginTop="@dimen/edittext_margin_createaccount">
        <android.support.design.widget.TextInputEditText
            android:id="@+id/idFrom"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/hint_from" />
    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/EditTextGrey"
        android:layout_marginTop="@dimen/edittext_margin_createaccount">
        <android.support.design.widget.TextInputEditText
            android:id="@+id/idTo"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/hint_to" />
    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/EditTextGrey"
        android:layout_marginTop="@dimen/edittext_margin_createaccount">
        <android.support.design.widget.TextInputEditText
            android:id="@+id/idOrderTitle"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/hint_order_title" />
    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/EditTextGrey"
        android:layout_marginTop="@dimen/edittext_margin_createaccount">
        <android.support.design.widget.TextInputEditText
            android:id="@+id/idOrderDescription"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/hint_order_description" />
    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/EditTextGrey"
        android:layout_marginTop="@dimen/edittext_margin_createaccount">
        <android.support.design.widget.TextInputEditText
            android:id="@+id/idMoneyToPay"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/hint_payment" />
    </android.support.design.widget.TextInputLayout>

    <Button
        android:id="@+id/button_request_order"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/button_text_request"/>

</LinearLayout>
</android.support.design.widget.CoordinatorLayout>

I want to take the TextInputEditText given by the user and save them in FirebaseDatabase .

What I have so far in backend is the following:

DomixApplication.java     package com.didierzuniga.domix;

import android.app.Application;
import android.content.Context;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

public class DomixApplication extends Application {

DatabaseReference orderReference;
Context context;

@Override
public void onCreate() {
    super.onCreate();

    FirebaseDatabase frbDatabase = FirebaseDatabase.getInstance();
    frbDatabase.setPersistenceEnabled(true);

    orderReference = frbDatabase.getReference("order");
    this.context = this;
}

public DatabaseReference getOrderReference() {
    return orderReference;
}

public Context getContext() {
    return context;
}
}

UserHomeActivity.class

public class UserHomeActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    DomixApplication app;
    DatabaseReference orderReference;

    @Bind(R.id.idFrom) TextInputEditText from;
    @Bind(R.id.idTo) TextInputEditText to;
    @Bind(R.id.idOrderTitle) TextInputEditText orderTitle;
    @Bind(R.id.idOrderDescription) TextInputEditText description;
    @Bind(R.id.idMoneyToPay) TextInputEditText payment;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user_home);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        ButterKnife.bind(this);

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open_user, R.string.navigation_drawer_close_user);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

    @OnClick(R.id.button_request_order)
    public void sendRequest(){
        String vFrom = from.getText().toString().trim();
        String vTo = to.getText().toString().trim();
        String vOrderTitle = orderTitle.getText().toString().trim();
        String vDescription = description.getText().toString().trim();
        String vPayment = payment.getText().toString().trim();

        Order order = new Order(vFrom, vTo, vOrderTitle, vDescription, vPayment);
        orderReference.push().setValue(order);
    }
...

Where should I call the url address of FirebaseDatabase ?

And what else should I add?