1. Install the extension
1. Install via App/Code
Unzip the file.
Create another directory called app/code/Bss/ChatGPT/. ChatGPT is the module's internal identifier. You can find it in the "composer.json" file in the extension ZIP file you downloaded, look at the node "psr-4".
This is what you call the directory, and then you put the contents of the extension ZIP file in there.
Upload the directory app/code/Bss/ChatGPT/ into the root directory of your Magento installation. The root directory of Magento is the directory that contains the directories "app", "bin", "lib" and more. All directories should match the existing directory structure.
Go to Magento 2 root directory.
Run: php bin/magento setup:upgrade.
Run: php bin/magento setup:static-content:deploy.
Run: php bin/magento setup:di:compile
Clear all Caches.
2. Install via Composer
Besides installing Magento 2 extensions via App/Code, installing via Composer is another very common and simple way used by a lot of Magento users.
Follow the guide here.