How to multiple checbox passing data to another activity and saving to Firebase

firstly I am sorry for my bad english...

I am new in Android and I have a register page include multiple checkboxes like reading book, playing an enstrument etc. In another activity, I save user's information in Firebase Realtime Database. But I can't passing the data of checkboxes to another page.

This is the Xml code of Checkboxes.

<CheckBox
                android:id="@+id/bisiklet_surmek_hobi"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="20dp"
                android:layout_marginRight="10dp"
                android:layout_marginBottom="10dp"
                android:background="@drawable/hobi_bisiklet_check_selector"
                android:button="@color/colorTransparent"
                android:fontFamily="@font/inter_bold"
                android:gravity="center_horizontal|center_vertical"
                android:letterSpacing="-0.03"
                android:shadowColor="#000000"
                android:shadowDy="3"
                android:shadowRadius="10"
                android:text="Bisiklet\nSürmek"
                android:textColor="@color/whiteColor" />

            <CheckBox
                android:id="@+id/satranc_hobi"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="20dp"
                android:layout_marginBottom="10dp"
                android:layout_toRightOf="@id/bisiklet_surmek_hobi"
                android:background="@drawable/hobi_satranc_check_selector"
                android:button="@null"
                android:fontFamily="@font/inter_bold"
                android:gravity="center_horizontal|center_vertical"
                android:letterSpacing="-0.03"
                android:shadowColor="#000000"
                android:shadowDy="3"
                android:shadowRadius="10"
                android:text="Satranç"
                android:textColor="@color/whiteColor" />

            <CheckBox
                android:id="@+id/enstruman_calmak_hobi"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/satranc_hobi"
                android:layout_alignLeft="@id/satranc_hobi"
                android:layout_marginBottom="10dp"
                android:background="@drawable/hobi_enstruman_check_selector"
                android:button="@null"
                android:fontFamily="@font/inter_bold"
                android:gravity="center_horizontal|center_vertical"
                android:letterSpacing="-0.03"
                android:shadowColor="#000000"
                android:shadowDy="3"
                android:shadowRadius="10"
                android:text="Enstrüman\nÇalmak"
                android:textColor="@color/whiteColor" />

            <CheckBox
                android:id="@+id/cizim_yapmak_hobi"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/bisiklet_surmek_hobi"
                android:layout_marginRight="10dp"
                android:layout_marginBottom="10dp"
                android:background="@drawable/hobi_cizim_check_selector"
                android:button="@null"
                android:fontFamily="@font/inter_bold"
                android:gravity="center_horizontal|center_vertical"
                android:letterSpacing="-0.03"
                android:shadowColor="#000000"
                android:shadowDy="3"
                android:shadowRadius="10"
                android:text="Çizim Yapmak"
                android:textColor="@color/whiteColor" />

I defined the checkboxes in Hobby_Activity.

    bisiklet_surmek_hobi = findViewById(R.id.bisiklet_surmek_hobi);
    satranc_hobi = findViewById(R.id.satranc_hobi);
    enstruman_calmak_hobi = findViewById(R.id.enstruman_calmak_hobi);
    cizim_yapmak_hobi = findViewById(R.id.cizim_yapmak_hobi);
    kitap_okumak_hobi = findViewById(R.id.kitap_okumak_hobi);
    cosplay_hobi = findViewById(R.id.cosplay_hobi);
    muzik_dinlemek_hobi = findViewById(R.id.muzik_dinlemek_hobi);

And this is the Last_Activity that I saved the datas in database.I used Intent function page by page.

    comp_phoneNumber = getIntent().getStringExtra("userPhone");
    user_FirstName = getIntent().getStringExtra("user_FirstName");
    user_Gender = getIntent().getStringExtra("user_Gender");
    user_Birthdate = getIntent().getStringExtra("user_Birthdate");

    

This is the realtime database function. This function is working very well.

public void storeNewUserData() {
    rootNode = FirebaseDatabase.getInstance();
    reference = rootNode.getReference("Users");

    UserHelperClass addNewUser = new UserHelperClass(comp_phoneNumber, user_FirstName, user_Gender, user_Birthdate);
    reference.child(comp_phoneNumber).setValue(addNewUser);
}

But I can't passing data of the checkboxes in Last_Activity and I don't know how to save checkboxes to under the user phone number.

Thank you in advance for your help.