Can any one suggest the best approach to populate the resource names in clarity from the external system ?
There are a couple of Services adapters that integrate resource data that may be able to help.
See https://www.ca.com/us/collateral/service-offering/ca-ppm-packaged-work-products.html for more details.
The two resource adapters from this list are the Microsoft Excel Interface for Resource and also the Resource Adapter.
If you’re on SaaS, this one comes free with Clarity.
Add-in: Integration Adaptor (CA PPM SaaS Only) - CA PPM SaaS - 15.6 - CA Technologies Documentation