You generally need an existing perpetual license key for R18 to activate it.
While Maxon prioritizes their latest Subscription releases, legacy users can often find R18 installers through their Maxon MyProducts portal if they have a perpetual license.
Maxon occasionally removes old installers. Contact Maxon support directly. They provide legacy download links via customer support tickets.
Once you have downloaded the official installer (approximately 8-10 GB), follow these steps: