Magento 1 is a legacy platform that is no longer maintained upstream. Use this only for legacy migrations or archival installs.
Magento 1 is not distributed by Adobe anymore. If you still need it, obtain a legacy package from your existing archive or a trusted vendor.
Extract the package to your web root and set ownership to the web server user.
Create a database and user, then grant permissions for the Magento 1 schema.
Open the site in a browser and complete the installation wizard.
Consider migrating to Magento Open Source (Magento 2). You can also reach out via our contact page.