This plugin will improve SEO by helping search enginess better index your site using sitemaps.

Noted That:

To install correctly this google-sitemap-generator.zip.
Fisrt Download the google-sitemap-generator.zip to your computer
Extract/Open google-sitemap-generator.zip to Your Computer.
Then, Find readme.txt file inside google-sitemap-generator.zip and Open readme.txt.
Now, Read the Requirements of this plugin. Which Wordpress Version and PHP Version are required to run this Plugin in Your Wordpress Site.
Then, Follow the the Tips Below.

Start the Tips:

1. First Download "google-sitemap-generator.zip" Plugin to your Local Computer. (Click Download)

2. Then, Login to your "yourdomain.com/wp-admin" Dashboard.

3. Then, Click on "Plugins" + "Add New" from left sidemenu of Dashboard.

4. Now, Click on "Upload Plugin" button.

5. Now, Browse "google-sitemap-generator.zip" Downloaded plugin from your computer, Where you downloaded google-sitemap-generator.zip According to Step – 1 Above then, click on "Install Now"

6. Now, Click on "Active Plugin"

7. Then, See left sidemenu. "Google XML Sitemaps" folder is added on left sidemenu. Now, Click on "Google XML Sitemaps" folder.

Noted that: If you do not see "Google XML Sitemaps" folder on left sidemenu then, see at left sidemenu "Settings" or "Tools".

8. Now you configure yourself oR Watch video tutorial below about Google XML Sitemaps Configurtions and Settings or How to work "Google XML Sitemaps" in your WordPress site.

After Activated Plugin According to Step-6 then,

Go to "Plugins" + "Installed Plugin" from Wordpress Admin Panel Leftside Menu.
or Direct go to: https://yourdomain/wp-admin/plugins.php
Then, Find "Google XML Sitemaps" Activated Plugin from Plugin List.
Then, Click on "Settings" from Plugin that is Google XML Sitemaps
Now, Edit/Add/Config the setting and Click on "Save Changes" button,

Guide
Install the plugin like you always install plugins, either by uploading it via FTP or by using the “Add Plugin” function of WordPress. Activate the plugin at the plugin administration page If you want: Open the plugin configuration page, which is located under Settings -> XML-Sitemap and customize settings like priorities and change frequencies. The plugin will automatically update your sitemap of you publish a post, so there is nothing more to do ????

Guide

Install the plugin like you always install plugins, either by uploading it via FTP or by using the “Add Plugin” function of WordPress.
Activate the plugin at the plugin administration page
If you want: Open the plugin configuration page, which is located under Settings -> XML-Sitemap and customize settings like priorities and change frequencies.
The plugin will automatically update your sitemap of you publish a post, so there is nothing more to do ????

your, site, using, sitemaps, index, better, improve, helping, search, enginess,

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Reffered: https://wordpress.org/