TestNG - providing parameters for class level test

I am running tests using TestNG, Java & Eclipse work-space. I can run tests in a number of ways. I can run a TestNG file, or I can run individual classes. If I run from an individual class, the parameters are not picked up from the TestNG.xml file. I may want to switch testings to a different URL. This form, given in Tutorials, does not work, & only produces errors.

import org.testng.annotations.Parameters;
import org.testng.annotations.Test;

public class ParameterizedTest1 {
   @Test
   @Parameters("myName")
   public void parameterTest(String myName) {
      System.out.println("Parameterized value is : " + myName);
   }
}

This is from a Tutorial at https://www.tutorialspoint.com/testng/testng_parameterized_test.htm

Error says this: [Utils] [ERROR] [Error] org.testng.TestNGException: Parameter 'url' is required by @Test on method addProjectTask but has not been marked @Optional or defined in C:\Users\SStaple\AppData\Local\Temp\testng-eclipse-38561327\testng-customsuite.xml

*** I called my parameter url. i.e:

@Test(groups = { "all", "projects", "create", "simple" })
@Parameters("url")
public void addProjectTask(String url) {
    System.out.println("Parameterized value is : " + url);

I don't want to have to re-code this every time I switch URL.

Testng.xml looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite allow-return-values="false" configfailurepolicy="skip"
    data-provider-thread-count="10" group-by-instances="false" guice-stage="DEVELOPMENT"
    junit="false" name="hardening-simple" parallel="none" preserve-order="true"
    skipfailedinvocationcounts="false" thread-count="5">
    <parameter name="browser" value="firefox" />
    <parameter name="url" value="https://url/#/" />
    <parameter name="printToFile" value="true" />
    <parameter name="trace" value="false" />
    <parameter name="opt" value="true" />
    <parameter name="customer" value="Demo" />
    <parameter name="network" value="NSG Designated Streets (Type 1/2)" />
    <parameter name="buildNo" value="025" />
    <parameter name="teamCity" value="false" />
    <parameter name="retest" value="0" />
    <parameter name="user" value="normal" />
    <listeners>
        <listener class-name="listeners.TestNGCustomReportListener" />
    </listeners>
    <test allow-return-values="false" group-by-instances="false"
        junit="false" name="firefoxTest" preserve-order="true"
        skipfailedinvocationcounts="false">
        <parameter name="browser" value="firefox" />
        <parameter name="url" value="https://url/#/" />
        <parameter name="opt" value="true" />
        <parameter name="user" value="normal" />
        <groups>
            <define name="simple">
                <include name="simple" />
            </define>
            <run>
                <include name="simple" />
                <exclude name="not-implemented" />
            </run>
        </groups>
        <classes>

Does anyone know the correct method?