PHP - Select Id e Insert hacia otra tabla

$sql1 = "SELECT id_home FROM pe_home WHERE mail_h = '$usuario'";

mysql_query($sql1);

$id = mysql_query($sql1);

$query3 = "INSERT INTO room ( id_home) VALUES ('$id')";

if ($link->query($query3) == TRUE){

    echo "<h5><br><br>Room Information Submitted Successfully</h5>";

}

else {

    echo "<h5><br><br>Error to Submitted Room Information</h5>" . $query3 . "<br>" . $link->error;}

// Create connection

$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection

if ($conn->connect_error) {

    die("Connection failed: " . $conn->connect_error);

}

$sql = "INSERT INTO MyGuests (firstname, lastname, email)

VALUES ('John', 'Doe', 'john@example.com')";

if ($conn->query($sql) === TRUE) {

    $last_id = $conn->insert_id;

    echo "New record created successfully. Last inserted ID is: " . $last_id;

} else {

    echo "Error: " . $sql . "<br>" . $conn->error;

}

$conn->close();