Error Installing QuickSubmit in OJS 3.3.0.10

Description of issue or problem I’m having:
I have been trying to install quickSubmit plugin on an OJS platform. First, I have issue installing from the plugin gallery. So i resolved to manual installation by following the steps on this forum.
I downloaded the latest version the QuickSubmit application fro github to the plugins/importexport/ folder.
I then perform the upgrade on the CLI using the following command

$ php tools/upgrades.php

Then I got the following error messages
PHP Fatal error: Uncaught Error: Class ‘PKP\plugins\ImportExportPlugin’ not found in /var/www//public_html/plugins/importexport/quickSubmit/QuickSubmitPlugin.inc.php:16
Stack trace:
#0 /var/www/
/public_html/plugins/importexport/quickSubmit/index.php(19): require_once()
#1 /var/www/
/public_html/lib/pkp/classes/plugins/PluginRegistry.inc.php(241): include(’/var/www/iljs.o…’)
#2 /var/www/
/public_html/lib/pkp/classes/plugins/PluginRegistry.inc.php(126): PluginRegistry::_instantiatePlugin()
#3 /var/www/
/public_html/lib/pkp/classes/plugins/PluginRegistry.inc.php(211): PluginRegistry::loadCategory()
#4 /var/www/
/public_html/lib/pkp/classes/install/Installer.inc.php(97): PluginRegistry::loadAllPlugins()
#5 /var/www/
/public_html/classes/install/Upgrade.inc.php(27): Installer->__construct()
#6 /var/www/
/public_html/lib/pkp/classes/cliTool/UpgradeTool.inc.php(86): Upgrade->__construct()
#7 /var/www/*****/public_html/lib/pkp/classes/cliTool/Up in /var/www/
**/public_html/plugins/importexport/quickSubmit/QuickSubmitPlugin.inc.php on line 16

Steps I took leading up to the issue:
I read some random article on the internet that suggest that I increase the max-execution-time in the php.ini file, which I did, yet no result

Hi @Olawale_Koledafe

How did you downloaded and uploaded the plugin to the folder? Are you using git clone or fetching the tar package? Did you use the correct plugin version URL (GitHub - pkp/quickSubmit at stable-3_3_0) ?

The upgrade script is not necessary to run if you install a plugin using the GUI Dashboard.

Best,
Israel

Thank you Israel, I am happy someone finally responded. I installed Quicksubmit via got clone, I read through the documentation on github, yet it refused to work.

P. S.

I had to install a fresh copy of OJS (thank God its a new journal site, so no article had been uploaded, so no need to worry about database).
I made sure I installed the Quicksubmit plugin, before anything else, and it worked.

Thank you.