1. Download the package from Github because the website packages contains additional modules which isn't working in a sub directory as they are for commercial purpose. https://www.prestashop.com/forums/topic/1085022-unable-to-install-prestashop-81x-in-a-subdirectory/
(The release package for 9.0.0 wasn't available on Github https://github.com/PrestaShop/PrestaShop/releases/tag/9.0.0 and in release notes link on Github i.e https://build.prestashop-project.org/news/2025/prestashop-9-0-available/ they have mentioned to download from https://prestashop.com/versions/
2. Keep root writable while installing manually.
3. Unzip prestashop files on server only. Let UI unzip the files. Before starting the installation make the zip on server and download.
4. [IMP] TAKE SQL DUMP WHEN INSTALLATION COMPLETES AND FILE DUMP ON ADMIN PANEL
5. check and 
	copy /admin/bundles/*
	copy /translations/* [Not required anymore]
	copy config/themes/* (Except config/themes/classic/shop1.json, need to configure this file) (Not required from 1.7.1.0)
	copy img/*
	copy mails/en/* except files which uses softurl
	copy modules/* except files which uses softurl
	Delete /var/cache/prod
6. Copy bootstrap.php from config folder and create _bootstrap.php and make following changes to get new_cookie_key :
"echo '<new_cookie_key>'.$key.'</new_cookie_key>';"
This is our change to generate the new_cookie_key, Also create clone_bootstrap.php and make changes to unset new_cookie_key>
7. If it is asked for country choose "United States" and Shop timezone as "US/Eastern"
8. Keep demo data "enabled" and SSL entry "blank" in manual installation.
9. While manual install - installation of modules : Install all modules (recommended)
10. PHP REQUIREMENT LINK: https://devdocs.prestashop-project.org/9/basics/installation/system-requirements/#php-requirements
11. No Documentation provided to upgrade prestashop 1.7.x.x hence we have not provided the same. http://doc.prestashop.com/dashboard.action
12. We have removed mcrypt extension because a user reported this via ticket.
13. [NA] config.php generates on visiting frontlink in manual installation.
14. Under [[dbprefix]]configuration table keep 'value' column blank for the following 'name' columns i.e : PS_ACCOUNTS_RSA_PRIVATE_KEY, PS_ACCOUNTS_RSA_PUBLIC_KEY and PS_ACCOUNTS_RSA_SIGN_DATA blank , as they are made again after logging into the admin panel.(By clicking on Modules-> Marketplace)
15. [NA] For our reference : Since Presta 8.0.1, while manual installation Prestashop is installed in maintenance mode and demo data isnt displayed . We have kept the same. To enable store users will have to go to admin panel -> click maintenance mode icon and check 'Enable Store' to enable store and display demo data content on frontend. (Requires in Prestashop commercial package)
16. Select 'classic theme' while manual installation.
17. We only make PS_ACCOUNTS_SHOP_STATUS,PS_CHECKOUT_SHOP_UUID_V4,PSX_UUID_V4 entries as the remaining entries gets created on verifying the account.