Noted That:

• To install correctly this gmail-comment-approval.zip.
• Fisrt Download the gmail-comment-approval.zip to your computer
• Extract/Open gmail-comment-approval.zip to Your Computer.
• Then, Find readme.txt file inside gmail-comment-approval.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 "gmail-comment-approval.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 "gmail-comment-approval.zip" Downloaded plugin from your computer, Where you downloaded gmail-comment-approval.zip According to Step – 1 Above then, click on "Install Now"

6. Now, Click on "Active Plugin"

7. Then, See left sidemenu. "Gmail Comment Approval" folder is added on left sidemenu. Now, Click on "Gmail Comment Approval" folder.

   Noted that: If you do not see "Gmail Comment Approval" folder on left sidemenu then, see at left sidemenu "Settings" or "Tools".

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

After Activated Plugin According to Step-6 then,

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

1. Upload gmail-inbox-action folder to the /wp-content/plugins/ directory
2. Activate the plugin through the ‘Plugins’ menu in WordPress.
3. For proper working you need to make sure that your emails are DKIM signed
4. Register your email with google: http://goo.gl/siU783

For detailed reference:
Visit WordPress Comment Approval Using Gmail