I have two activities. from the first one, I call the second one, and from the second one, I call a fragment by pressing a button inside the second activity, but when I click on the button in the first activity to trigger the second activity, a fragment is immediately called

the code for calling the second activity

 val chooseActivityButton = findViewById<Button>(R.id.GoActivity)
        chooseActivityButton.setOnClickListener {
            val intent = Intent(this, chooseLab::class.java)
            // start your next activity
            startActivity(intent)
        }

the code for calling the fragment

    fun onClick(view: View){
        setContentView(R.layout.activity_choose_lab);
        val callFragmentFirst = findViewById<Button>(R.id.call_fragment_first)

        callFragmentFirst.setOnClickListener {
            val fragmentTransaction: FragmentTransaction = supportFragmentManager.beginTransaction()
            fragmentTransaction.replace(R.id.FirstFragmentContainer, FirstFragment()) // или .replace(R.id....)

            fragmentTransaction.commit()
        }
    }

xml fragment conteiner

<androidx.fragment.app.FragmentContainerView
        android:id="@+id/FirstFragmentContainer"
        android:name="com.example.myapplication.FirstFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"

        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />