Log in to the Trimble Account Management Portal. Under the "Plan Settings" or "Products" tab, your legacy license information may be listed.
If you have a modern subscription, activation is tied to your Trimble ID rather than a serial number: Sign-In Activation Sketchup Pro 2022 Serial Number And Authorization Code
The 2022 version of SketchUp Pro comes with several exciting new features, including: Log in to the Trimble Account Management Portal
To activate SketchUp Pro 2022, follow these steps: including: To activate SketchUp Pro 2022
If you still need your specific serial number for record-keeping or a classic license: License not recognized - SketchUp Forums
If you have your serial number and authorization code ready, follow these steps to activate Sketchup Pro 2022: