How to handle non static methods?

Question

I'm working on some code to insert a employee into a database when I do this for me I've done Database.dao().addEmployee(emp); it says non static method 'dao' cannot be referenced from a static context. If I add it to static then the addEmployee() becomes an error as well. I am unsure what this means as I am a very beginner. My dao is an interface for the database if that helps make sense of what I am trying to do. Any help would be muchly appreciated. Here is my code:

package com.example.a2;

import androidx.appcompat.app.AppCompatActivity;
import androidx.room.Room;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class MainActivity extends AppCompatActivity {

public static Database database;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    database = Room.databaseBuilder(getApplicationContext(), Database.class, "employeedb").allowMainThreadQueries().build();

    final Button logInBt = findViewById(R.id.buttonLogIn);
    final EditText userEditText = findViewById(R.id.editTextTextPersonName);
    final EditText passwordEditText = findViewById(R.id.editTextTextPassword);

    logInBt.setOnClickListener(new View.OnClickListener() {
        public void  onClick(View view) {
            Intent i = new Intent(getApplicationContext(), Inventory.class);
            startActivity(i);

            // Obtaining data from the interface
            String userName = userEditText.getText().toString();
            String password = passwordEditText.getText().toString();

            // Create new employee object
            Employee emp = new Employee();
            emp.setUserName(userName);
            emp.setPassword(password);
            
            //Insert customer into database
            Database.dao().addEmployee(emp);

            //Display a message
            Toast.makeText(getBaseContext(), "Added successfully!", Toast.LENGTH_SHORT).show();

            // Clear the text
            userEditText.setText("");
            passwordEditText.setText("");
        }
    });

}

}