How to make forms visible built through forms api.

i have just started learning drupal. i have to create a form(form code is given below),but i don't know what to do with this code i.e where to save this code and how to make it visible as a form so that i can enter data and perform further action.

please provide me detailed solution(each and every minor step) about creating a form in drupal.

function test_form($form_state) {
  // Access log settings:
  $options = array('1' => t('Enabled'), '0' => t('Disabled'));
  $form['access'] = array(
    '#type' => 'fieldset',
    '#title' => t('Access log settings'),
    '#tree' => TRUE,
  );
  $form['access']['log'] = array(
    '#type' => 'radios',
    '#title' => t('Log'),
    '#default_value' =>  variable_get('log', 0),
    '#options' => $options,
    '#description' => t('The log.'),
  );
  $period = drupal_map_assoc(array(3600, 10800, 21600, 32400, 43200, 86400, 172800, 259200, 604800, 1209600, 2419200, 4838400, 9676800), 'format_interval');
  $form['access']['timer'] = array(
    '#type' => 'select',
    '#title' => t('Discard logs older than'),
    '#default_value' => variable_get('timer', 259200),
    '#options' => $period,
    '#description' => t('The timer.'),
  );
  // Description
  $form['details'] = array(
    '#type' => 'fieldset',
    '#title' => t('Details'),
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
  );
  $form['details']['description'] = array(
    '#type' => 'textarea',
    '#title' => t('Describe it'),
    '#default_value' =>  variable_get('description', ''),
    '#cols' => 60,
    '#rows' => 5,
    '#description' => t('Log description.'),
  );
  $form['details']['admin'] = array(
    '#type' => 'checkbox',
    '#title' => t('Only admin can view'),
    '#default_value' => variable_get('admin', 0),
  );
  $form['name'] = array(
    '#type' => 'textfield',
    '#title' => t('Name'),
    '#size' => 30,
    '#maxlength' => 64,
    '#description' => t('Enter the name for this group of settings'),
  );
  $form['hidden'] = array('#type' => 'value', '#value' => 'is_it_here');
  $form['submit'] = array('#type' => 'submit', '#value' => t('Save'));
  return $form;
}

function test_page() {
  return drupal_get_form('test_form');
}